arm: dts: ls1088a-rdb: replace 'xgmii' with '10gbase-r'

arm: dts: ls1088a-rdb: replace 'xgmii' with '10gbase-r'

When the first device tree description was added for the ethernet nodes,
the 2 10G ports on the LS1088ARDB were wrongly described as 'xgmii'.

Fix this by replacing the two last occurrences of 'xgmii' in the device
trees of the Layerscape DPAA2 devices.

Fixes: 9de2fdd7d65a ("arm: dts: ls1088ardb: add DPMAC and PHY nodes")
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>