mm/shmem.c: make array 'values' static const, makes object smaller

Don't populate the array 'values' on the stack but instead make it static
const.  Makes the object code smaller by 111 bytes.

Before:
   text	   data	    bss	    dec	    hex	filename
 108612	  11169	    512	 120293	  1d5e5	mm/shmem.o

After:
   text	   data	    bss	    dec	    hex	filename
 108437	  11233	    512	 120182	  1d576	mm/shmem.o

(gcc version 9.2.1, amd64)

Link: http://lkml.kernel.org/r/20190906143012.28698-1-colin.king@canonical.comSigned-off-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/shmem.c

@@ -3932,7 +3932,7 @@ int __init shmem_init(void)
 static ssize_t shmem_enabled_show(struct kobject *kobj,
 		struct kobj_attribute *attr, char *buf)
 {
-	int values[] = {
+	static const int values[] = {
 		SHMEM_HUGE_ALWAYS,
 		SHMEM_HUGE_WITHIN_SIZE,
 		SHMEM_HUGE_ADVISE,