[SPARC]: Kill extern decl of 'panic_setup'.

This was made static in kernel/panic.c a long time ago.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc/kernel/setup.c

@@ -191,7 +191,6 @@ extern int prom_probe_memory(void);
 extern void sun4c_probe_vac(void);
 extern char cputypval;
 extern unsigned long start, end;
-extern void panic_setup(char *, int *);
 
 extern unsigned short root_flags;
 extern unsigned short root_dev;

arch/sparc64/kernel/setup.c

@@ -157,8 +157,6 @@ static void __init boot_flags_init(char *commands)
 	}
 }
 
-extern void panic_setup(char *, int *);
-
 extern unsigned short root_flags;
 extern unsigned short root_dev;
 extern unsigned short ram_flags;