arm64: dts: mediatek: mt7622: introduce nodes for Wireless Ethernet Dispatch

Introduce wed0 and wed1 nodes in order to enable offloading forwarding
between ethernet and wireless devices on the mt7622 chipset.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: David S. Miller <davem@davemloft.net>