Ethernet support for ar9331 is upstream now. So, drop every thing what
is provided by upstream devicetree and rename compatible in the driver.

barebox network driver will need more work to be upstream compliant. For
example we should not request or touch the gmac register directly. Since
currently it is not clear how this should be implemented, patch the
upstream dts with reg-names = "ge0", "gmac".

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>