net: macb: Prepare for driver-model conversion

net: macb: Prepare for driver-model conversion

Adjust this driver to avoid using struct netdev in functions that driver
model will call. Also refactor the receive function to be compatible with
driver model.

Signed-off-by: Simon Glass <[email protected]>
Reviewed-by: Heiko Schocher <[email protected]>
Tested-on: smartweb, corvus, taurus, axm
Tested-by: Heiko Schocher <[email protected]>
Reviewed-by: Joe Hershberger <[email protected]>
Acked-by: Joe Hershberger <[email protected]>
Reviewed-by: Andreas Bießmann <[email protected]>