rocker: add general purpose registers definitions

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
rocker: add basic support for rocker ports

Create a dummy netdevice for each.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
rocker: add ethtool stub

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
rocker: implement link state change handling

Signed-off-by: Jiri Pirko <jiri@resnulli.us>