ipq40xx: Convert Google Wifi to DSA, reenable

ipq40xx: Convert Google Wifi to DSA, reenable

Undo parts of these:

116feb4a1cad ipq40xx: remove non-converted network configs
db19efee9512 ipq40xx: disable boards not converted to DSA

Reintroduce the DT paths /soc/edma@c080000/gmac{0,1}, because the stock
bootloader has memorized them (instead of following aliases); then plug
the MAC address back in via 05_set_iface_mac_ipq40xx.sh, since the
'local-mac-address' property is no longer in the correct node.

Cc: David Bauer <mail@david-bauer.net>
Cc: Robert Marko <robert.marko@sartura.hr>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>