drivers/block/mtip32xx: remove the null check for debugfs_remove_recursive

debugfs_remove_recursive has taken null pointer into account. So it is
safe to drop the null check before calling the function.
Signed-off-by: Nzhong jiang <zhongjiang@huawei.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

drivers/block/mtip32xx/mtip32xx.c

@@ -2575,8 +2575,7 @@ static int mtip_hw_debugfs_init(struct driver_data *dd)
 
 static void mtip_hw_debugfs_exit(struct driver_data *dd)
 {
-	if (dd->dfs_node)
-		debugfs_remove_recursive(dd->dfs_node);
+	debugfs_remove_recursive(dd->dfs_node);
 }
 
 /*