ADMAv2.0 is plagued by RX hangs which can't easily detected and happen upon
receival of a corrupted Ethernet frame.

Use ADMAv1 instead which is also still present and usable, and doesn't
suffer from that problem.

Fixes: 197c9e9b ("net: ethernet: mtk_eth_soc: introduce support for mt7986 chipset")
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/57cef74bbd0c243366ad1ff4221e3f72f437ec80.1715164770.git.daniel@makrotopia.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>