net: bcmgenet: Initial bcmgenet ACPI support

The rpi4 is capable of booting in ACPI mode with the latest
edk2-platform commits. As such it would be helpful if the genet
platform device were usable.

To achieve this we add a new MODULE_DEVICE_TABLE, and convert
a few dt specific methods to their generic device_ calls. Until
the next patch, ACPI based machines will fallback on random
mac addresses.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>