Add code/constants for detecting imx6ul (ultralite) chips, a species of
imx6 based on a single cortex-a7 core. Other changes to imx6 drivers
and support code are needed to fully support the imx6ul.
if_ffec: Add imx6ul SoC support, and get the PHY number from the FDT data.
If there is no phy-handle property, fall back to using MII_PHY_ANY.
This still doesn't support an mdio bus with multiple PHYs on it, or the
possibility that the PHY being used by this instance of ffec is on the
mdio bus of some other instance (which is now a possibility with imx6ul).
Adding that support will require changes in fdt_get_phyaddr(), which is
currently making some assumptions that don't work with modern fdt data.