IPoIB: Remove unnecessary test for NULL before debugfs_remove()

Fix checkpatch warning:

    WARNING: debugfs_remove(NULL) is safe this check is probably not required
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/ulp/ipoib/ipoib_fs.c

@@ -281,10 +281,8 @@ void ipoib_delete_debug_files(struct net_device *dev)
 {
 	struct ipoib_dev_priv *priv = netdev_priv(dev);
 
-	if (priv->mcg_dentry)
-		debugfs_remove(priv->mcg_dentry);
-	if (priv->path_dentry)
-		debugfs_remove(priv->path_dentry);
+	debugfs_remove(priv->mcg_dentry);
+	debugfs_remove(priv->path_dentry);
 }
 
 int ipoib_register_debugfs(void)