net: stmmac: dwmac-meson8b: Fix an error handling path in 'meson8b_dwmac_probe()'

If 'of_device_get_match_data()' fails, we need to release some resources as
done in the other error handling path of this function.

Fixes: efacb568 ("net: stmmac: dwmac-meson: extend phy mode setting")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>