Define  the Porter board dependent part of the Ether device node.
Enable DHCP and NFS root for the kernel booting.

This  patch  is analogous to the commit 26b0d2cf ("ARM: shmobile:
henninger: add Ether DT support") as there  are no differences between
those boards in this respect.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>