ecryptfs: drop null test before destroy functions

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);
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>

fs/ecryptfs/main.c

@@ -738,7 +738,6 @@ static void ecryptfs_free_kmem_caches(void)
 		struct ecryptfs_cache_info *info;
 
 		info = &ecryptfs_cache_infos[i];
-		if (*(info->cache))
 		kmem_cache_destroy(*(info->cache));
 	}
 }