Add ethernet0 and ethernet1 aliases into the imx28.dtsi file, as
that is what most bootloaders use to pass MAC address. The bootloader
seeks for this alias and adds "mac-address" and "local-mac-address"
properties to the aliased node. This fixes issues with FEC having
NULL MAC address when update_fec_mac_prop() wasn't called. And
not all boards call update_fec_mac_prop() .