staging: dpaa2-ethsw: read the port state from firmware

Rely on the port state seen by the firmware since it will also be the
one erroring out when trying to setup anything major when the port is
up.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/20200721091919.20394-6-ioana.ciornei@nxp.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>