slub: fix atomic usage in any_slab_objects()

any_slab_objects() does an atomic_read on an atomic_long_t, this
fixes it to use atomic_long_read instead.

Signed-off-by: Benjamin Herrenschmidt <[e-mail]>
Cc: Christoph Lameter <[e-mail]>
Cc: Pekka Enberg <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

mm/slub.c

···
 		if (!n)
 			continue;
 
-		if (atomic_read(&n->total_objects))
+		if (atomic_long_read(&n->total_objects))
 			return 1;
 	}
 	return 0;