kasan: make get_wild_bug_type() static

kasan: make get_wild_bug_type() static

The helper function get_wild_bug_type() does not need to be in global
scope, so make it static.

Cleans up sparse warning:

  "symbol 'get_wild_bug_type' was not declared. Should it be static?"

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Colin Ian King <[email protected]>
Acked-by: Dmitry Vyukov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>