ucc_geth: handle passing of RX-only and TX-only internal delay PHY connection type parameters

Extend the RGMII-Internal Delay specification case to include
TX-only and RX-only variants.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Tested-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Li Yang <leoli@freescale.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>