net: ethernet: mtk_eth_soc: fix RSTCTRL_PPE{0,1} definitions

Fix RSTCTRL_PPE0 and RSTCTRL_PPE1 register mask definitions for
MTK_NETSYS_V2.
Remove duplicated definitions.

Fixes: 160d3a9b

 ("net: ethernet: mtk_eth_soc: introduce MTK_NETSYS_V2 support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>