net: ethernet: mtk_eth_soc: fix state in __mtk_foe_entry_clear

Setting ib1 state to MTK_FOE_STATE_UNBIND in __mtk_foe_entry_clear
routine as done by commit 0e80707d

 ("net: ethernet: mtk_eth_soc:
fix typo in __mtk_foe_entry_clear") breaks flow offloading, at least
on older MTK_NETSYS_V1 SoCs, OpenWrt users have confirmed the bug on
MT7622 and MT7621 systems.
Felix Fietkau suggested to use MTK_FOE_STATE_INVALID instead which
works well on both, MTK_NETSYS_V1 and MTK_NETSYS_V2.

Tested on MT7622 (Linksys E8450) and MT7986 (BananaPi BPI-R3).

Suggested-by: Felix Fietkau <nbd@nbd.name>
Fixes: 0e80707d ("net: ethernet: mtk_eth_soc: fix typo in __mtk_foe_entry_clear")
Fixes: 33fc42de

 ("net: ethernet: mtk_eth_soc: support creating mac address based offload entries")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/YzY+1Yg0FBXcnrtc@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>