microblaze: Fix sparse warning - sw_exceptions

Function sw_exception is linked with asm code.

Warning log:
CHECK   arch/microblaze/kernel/exceptions.c
arch/microblaze/kernel/exceptions.c:53:6: warning: symbol 'sw_exception' was not declared. Should it be static?
Signed-off-by: NMichal Simek <monstr@monstr.eu>

arch/microblaze/include/asm/exceptions.h

@@ -66,6 +66,8 @@
 asmlinkage void full_exception(struct pt_regs *regs, unsigned int type,
 							int fsr, int addr);
 
+asmlinkage void sw_exception(struct pt_regs *regs);
+
 void die(const char *str, struct pt_regs *fp, long err);
 void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr);
 

arch/microblaze/kernel/exceptions.c

@@ -50,7 +50,7 @@ void die(const char *str, struct pt_regs *fp, long err)
 }
 
 /* for user application debugging */
-void sw_exception(struct pt_regs *regs)
+asmlinkage void sw_exception(struct pt_regs *regs)
 {
 	_exception(SIGTRAP, regs, TRAP_BRKPT, regs->r16);
 	flush_dcache_range(regs->r16, regs->r16 + 0x4);