mm: Fix warning on make htmldocs caused by slab.c

This patch fixed following errors while make htmldocs
Warning(/mm/slab.c:1956): No description found for parameter 'page'
Warning(/mm/slab.c:1956): Excess function parameter 'slabp' description in 'slab_destroy'

Incorrect function parameter "slabp" was set instead of "page"
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

mm/slab.c

@@ -1946,7 +1946,7 @@ static void slab_destroy_debugcheck(struct kmem_cache *cachep,
 /**
  * slab_destroy - destroy and release all objects in a slab
  * @cachep: cache pointer being destroyed
- * @slabp: slab pointer being destroyed
+ * @page: page pointer being destroyed
  *
  * Destroy all the objs in a slab, and release the mem back to the system.
  * Before calling the slab must have been unlinked from the cache.  The