Remove unneeded NULL test.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@ expression x; @@
-if (x != NULL) {
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
  x = NULL;
-}
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
        drc_hashtbl = NULL;
        drc_hashsize = 0;
 
-       if (drc_slab) {
-               kmem_cache_destroy(drc_slab);
-               drc_slab = NULL;
-       }
+       kmem_cache_destroy(drc_slab);
+       drc_slab = NULL;
 }
 
 /*