Do major DTS cleanup.

Make PHY modes of eth1 (dual-PHY NIC) consistent. The PHY names are:

* phy-def - matalic build-in ethernet, SGMII mode
* phy-sfp - SFP cage, 1000BASE-X
* phy-sfp-noneg - SFP cage, 1000BASE-X forced to link up, 1000/full
* phy-sfp-sgmii - SFP cage, SGMII mode

Add 1000BASE-X noneg mode:
Omnia can house certain SFP modules that need the L2 to force 1000BASE-X
mode without autonegotiation. Add this mode that can by selected by PHY
select in /sys filesystem.