stmmac: dwmac-mediatek: fix resource leak in probe

If mediatek_dwmac_clks_config() fails, then call stmmac_remove_config_dt()
before returning.  Otherwise it is a resource leak.

Fixes: fa4b3ca6 ("stmmac: dwmac-mediatek: fix clock issue")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YuJ4aZyMUlG6yGGa@kili


Signed-off-by: Jakub Kicinski <kuba@kernel.org>