h8300: Fix die()

Fix h8300's die() to take care of a number of problems:

    CC      arch/h8300/kernel/traps.o
  In file included from arch/h8300/include/asm/bitops.h:10,
                   from include/linux/bitops.h:22,
                   from include/linux/kernel.h:17,
                   from include/linux/sched.h:54,
                   from arch/h8300/kernel/traps.c:18:
  arch/h8300/include/asm/system.h:136: warning: 'struct pt_regs' declared inside parameter list
  arch/h8300/include/asm/system.h:136: warning: its scope is only this definition or declaration, which is probably not what you want
  arch/h8300/kernel/traps.c💯 error: conflicting types for 'die'
  arch/h8300/include/asm/system.h:136: error: previous declaration of 'die' was here
  make[2]: *** [arch/h8300/kernel/traps.o] Error 1

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/h8300/include/asm/system.h

@@ -3,6 +3,8 @@
 
 #include <linux/linkage.h>
 
+struct pt_regs;
+
 /*
  * switch_to(n) should switch tasks to task ptr, first checking that
  * ptr isn't the current task, in which case it does nothing.  This
@@ -155,6 +157,6 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz
 
 #define arch_align_stack(x) (x)
 
-void die(char *str, struct pt_regs *fp, unsigned long err);
+extern void die(const char *str, struct pt_regs *fp, unsigned long err);
 
 #endif /* _H8300_SYSTEM_H */

arch/h8300/kernel/traps.c

@@ -96,7 +96,7 @@ static void dump(struct pt_regs *fp)
 	printk("\n\n");
 }
 
-void die(char *str, struct pt_regs *fp, unsigned long err)
+void die(const char *str, struct pt_regs *fp, unsigned long err)
 {
 	static int diecount;