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/20170622090049.10658-1-colin.king@canonical.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/kasan/report.c

@@ -107,7 +107,7 @@ static const char *get_shadow_bug_type(struct kasan_access_info *info)
 	return bug_type;
 }
 
-const char *get_wild_bug_type(struct kasan_access_info *info)
+static const char *get_wild_bug_type(struct kasan_access_info *info)
 {
 	const char *bug_type = "unknown-crash";