net: ethernet: mediatek: remove return value check of `mtk_wed_hw_add_debugfs`

Smatch complains that:
mtk_wed_hw_add_debugfs() warn: 'dir' is an error pointer or valid

Debugfs checks are generally not supposed to be checked
for errors and it is not necessary here.

fix it by just deleting the dead code.
Signed-off-by: Wang Zhang <silver_code@hust.edu.cn>
Reviewed-by: Dongliang Mu <dzm91@hust.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/mtk_wed_debugfs.c

@@ -252,8 +252,6 @@ void mtk_wed_hw_add_debugfs(struct mtk_wed_hw *hw)
 
 	snprintf(hw->dirname, sizeof(hw->dirname), "wed%d", hw->index);
 	dir = debugfs_create_dir(hw->dirname, NULL);
-	if (!dir)
-		return;
 
 	hw->debugfs_dir = dir;
 	debugfs_create_u32("regidx", 0600, dir, &hw->debugfs_reg);