kconfig: move strhash() to util.c as a global function

Remove the 'static' qualifier from strhash() so that it can be accessed
from other files. Move it to util.c, which is a more appropriate location.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/kconfig/lkc.h

@@ -52,6 +52,7 @@ static inline void xfwrite(const void *str, size_t len, size_t count, FILE *out)
 }
 
 /* util.c */
+unsigned int strhash(const char *s);
 const char *file_lookup(const char *name);
 void *xmalloc(size_t size);
 void *xcalloc(size_t nmemb, size_t size);