mm: slab.h: wrap the whole file with guarding macro

Guarding section:
	#ifndef MM_SLAB_H
	#define MM_SLAB_H
	...
	#endif
currently doesn't cover the whole mm/slab.h. It seems like it was
done unintentionally.

Wrap the whole file by moving closing #endif to the end of it.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slab.h

@@ -260,7 +260,6 @@ static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 	WARN_ON_ONCE(1);
 	return s;
 }
-#endif
 
 #ifndef CONFIG_SLOB
 /*
@@ -311,3 +310,5 @@ static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 
 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 void slab_stop(struct seq_file *m, void *p);
+
+#endif /* MM_SLAB_H */