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: David S. Miller <davem@davemloft.net>
                return;
        kfree(rsk_prot->slab_name);
        rsk_prot->slab_name = NULL;
-       if (rsk_prot->slab) {
-               kmem_cache_destroy(rsk_prot->slab);
-               rsk_prot->slab = NULL;
-       }
+       kmem_cache_destroy(rsk_prot->slab);
+       rsk_prot->slab = NULL;
 }
 
 static int req_prot_init(const struct proto *prot)
        list_del(&prot->node);
        mutex_unlock(&proto_list_mutex);
 
-       if (prot->slab != NULL) {
-               kmem_cache_destroy(prot->slab);
-               prot->slab = NULL;
-       }
+       kmem_cache_destroy(prot->slab);
+       prot->slab = NULL;
 
        req_prot_cleanup(prot->rsk_prot);