AT91RM9200 Ethernet: Support additional PHYs

Add support for a number of new PHY's in the AT91RM9200 Ethernet driver.
- Teridian 78Q21x3
- SMSC LAN83C185
  (Patch from Luca Gamma)
- National Semiconductor DP83848
  (Patches from Ivan Kuten & Thomas Foldesi)

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>