m68k: sun3/3x: Add and use "sun3.h"

When building with W=1:

    arch/m68k/sun3/idprom.c:86:6: warning: no previous prototype for ‘sun3_get_model’ [-Wmissing-prototypes]
       86 | void sun3_get_model(char *model)
	  |      ^~~~~~~~~~~~~~
    arch/m68k/sun3/config.c:53:24: warning: no previous prototype for ‘sun3_init’ [-Wmissing-prototypes]
       53 | asmlinkage void __init sun3_init(void)
	  |                        ^~~~~~~~~
    arch/m68k/sun3/mmu_emu.c:117:6: warning: no previous prototype for ‘print_pte_vaddr’ [-Wmissing-prototypes]
      117 | void print_pte_vaddr (unsigned long vaddr)
	  |      ^~~~~~~~~~~~~~~
    arch/m68k/sun3/mmu_emu.c:126:13: warning: no previous prototype for ‘mmu_emu_init’ [-Wmissing-prototypes]
      126 | void __init mmu_emu_init(unsigned long bootmem_end)
	  |             ^~~~~~~~~~~~
    arch/m68k/sun3/mmu_emu.c:353:5: warning: no previous prototype for ‘mmu_emu_handle_fault’ [-Wmissing-prototypes]
      353 | int mmu_emu_handle_fault (unsigned long vaddr, int read_flag, int kernel_fault)
	  |     ^~~~~~~~~~~~~~~~~~~~
    arch/m68k/sun3/leds.c:6:6: warning: no previous prototype for ‘sun3_leds’ [-Wmissing-prototypes]
	6 | void sun3_leds(unsigned char byte)
	  |      ^~~~~~~~~
    arch/m68k/sun3/intersil.c:27:5: warning: no previous prototype for ‘sun3_hwclk’ [-Wmissing-prototypes]
       27 | int sun3_hwclk(int set, struct rtc_time *t)
	  |     ^~~~~~~~~~
    arch/m68k/sun3x/config.c:30:6: warning: no previous prototype for ‘sun3_leds’ [-Wmissing-prototypes]
       30 | void sun3_leds(unsigned char byte)
	  |      ^~~~~~~~~

Fix this by introducing a new header file "sun3.h" for holding the
prototypes of functions implemented in arch/m68k/sun3/ and
arch/m68k/sun3x/.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/87856ef9ef8955f459fb691faca921c0a688bc80.1694613528.git.geert@linux-m68k.org

arch/m68k/kernel/traps.c

@@ -364,7 +364,7 @@ static inline void access_error040(struct frame *fp)
 #if defined(CONFIG_SUN3)
 #include <asm/sun3mmu.h>
 
-extern int mmu_emu_handle_fault (unsigned long, int, int);
+#include "../sun3/sun3.h"
 
 /* sun3 version of bus_error030 */
 

arch/m68k/mm/sun3kmap.c

@@ -18,11 +18,9 @@
 #include <asm/io.h>
 #include <asm/sun3mmu.h>
 
-#undef SUN3_KMAP_DEBUG
+#include "../sun3/sun3.h"
 
-#ifdef SUN3_KMAP_DEBUG
-extern void print_pte_vaddr(unsigned long vaddr);
-#endif
+#undef SUN3_KMAP_DEBUG
 
 extern void mmu_emu_map_pmeg (int context, int vaddr);
 

arch/m68k/mm/sun3mmu.c

@@ -24,7 +24,7 @@
 #include <asm/machdep.h>
 #include <asm/io.h>
 
-extern void mmu_emu_init (unsigned long bootmem_end);
+#include "../sun3/sun3.h"
 
 const char bad_pmd_string[] = "Bad pmd in pte_alloc: %08lx\n";
 

arch/m68k/sun3/config.c

@@ -35,11 +35,11 @@
 #include <asm/sun3ints.h>
 #include <asm/config.h>
 
+#include "sun3.h"
+
 char sun3_reserved_pmeg[SUN3_PMEGS_NUM];
 
 static void sun3_sched_init(void);
-extern void sun3_get_model (char* model);
-extern int sun3_hwclk(int set, struct rtc_time *t);
 
 volatile char* clock_va;
 extern unsigned long availmem;

arch/m68k/sun3/idprom.c

@@ -17,6 +17,8 @@
 #include <asm/idprom.h>
 #include <asm/machines.h>  /* Fun with Sun released architectures. */
 
+#include "sun3.h"
+
 struct idprom *idprom;
 EXPORT_SYMBOL(idprom);
 

arch/m68k/sun3/intersil.c

@@ -17,6 +17,7 @@
 #include <asm/intersil.h>
 #include <asm/machdep.h>
 
+#include "sun3.h"
 
 /* bits to set for start/run of the intersil */
 #define STOP_VAL (INTERSIL_STOP | INTERSIL_INT_ENABLE | INTERSIL_24H_MODE)

arch/m68k/sun3/leds.c

@@ -3,6 +3,8 @@
 #include <asm/sun3mmu.h>
 #include <asm/io.h>
 
+#include "sun3.h"
+
 void sun3_leds(unsigned char byte)
 {
 	unsigned char dfc;

arch/m68k/sun3/mmu_emu.c

@@ -27,6 +27,7 @@
 #include <asm/mmu_context.h>
 #include <asm/dvma.h>
 
+#include "sun3.h"
 
 #undef DEBUG_MMU_EMU
 #define DEBUG_PROM_MAPS

arch/m68k/sun3/sun3.h

@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/linkage.h>
+
+struct rtc_time;
+
+/* config.c */
+asmlinkage void sun3_init(void);
+
+/* idprom.c */
+void sun3_get_model(char *model);
+
+/* intersil.c */
+int sun3_hwclk(int set, struct rtc_time *t);
+
+/* leds.c */
+void sun3_leds(unsigned char byte);
+
+/* mmu_emu.c */
+void mmu_emu_init(unsigned long bootmem_end);
+int mmu_emu_handle_fault(unsigned long vaddr, int read_flag, int kernel_fault);
+void print_pte_vaddr(unsigned long vaddr);

arch/m68k/sun3/sun3ints.c

@@ -17,7 +17,7 @@
 #include <asm/irq_regs.h>
 #include <linux/seq_file.h>
 
-extern void sun3_leds (unsigned char);
+#include "sun3.h"
 
 void sun3_disable_interrupts(void)
 {

arch/m68k/sun3x/config.c

@@ -22,11 +22,10 @@
 #include <asm/config.h>
 
 #include "time.h"
+#include "../sun3/sun3.h"
 
 volatile char *clock_va;
 
-extern void sun3_get_model(char *model);
-
 void sun3_leds(unsigned char byte)
 {