net: ethernet: mtk_eth_soc: delete some dead code

The debugfs_create_dir() function never returns NULL.  It does return
error pointers but in normal situations like this there is no need to
check for errors.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20211217071037.GE26548@kiliSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mediatek/mtk_ppe_debugfs.c

@@ -207,9 +207,6 @@ int mtk_ppe_debugfs_init(struct mtk_ppe *ppe)
 	struct dentry *root;
 
 	root = debugfs_create_dir("mtk_ppe", NULL);
-	if (!root)
-		return -ENOMEM;
-
 	debugfs_create_file("entries", S_IRUGO, root, ppe, &fops_all);
 	debugfs_create_file("bind", S_IRUGO, root, ppe, &fops_bind);