dtb: xgene: Add rxlos-gpios property

Added rxlos GPIO mapping by adding rxlos-gpios property.

Signed-off-by: Quan Nguyen <qnguyen@apm.com>
Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Tested-by: Fushen Chen <fchen@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>