microblaze: Fix sparse warning - unwind.c

Warning log:
CHECK   arch/microblaze/kernel/unwind.c
arch/microblaze/kernel/unwind.c:186:6: warning: symbol 'microblaze_unwind_inner' was not declared. Should it be static?

Signed-off-by: Michal Simek <monstr@monstr.eu>
1 file changed