migrate ucc_geth to use the common phylib code.

There are several side effects from doing this:

o deprecate 'interface' property specification present
  in some old device tree source files in
  favour of a split 'max-speed' and 'interface-type'
  description to appropriately match definitions
  in include/linux/phy.h.  Note that 'interface' property
  is still honoured if max-speed or interface-type
  are not present (backward compatible).
o compile-time CONFIG_UGETH_HAS_GIGA is eliminated
  in favour of probe time speed derivation logic.
o adjust_link streamlined to only operate on maccfg2
  and upsmr.r10m, instead of reapplying static initial
  values related to the interface-type.
o Addition of UEC MDIO of_platform driver requires
  platform code add 'mdio' type to id list
  prior to calling of_platform_bus_probe (separate patch).
o ucc_struct_init introduced to reduce ucc_geth_startup
  complexity.
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>