Add support for Eukrea CPUAT91 SBC

CPUAT91 is built around Atmel's AT91RM9200 and has up to 16MB of NOR
flash, up to 128MB of SDRAM, and includes a Micrel KS8721 PHY in RMII
mode.

Signed-off-by: Eric Benard <eric@eukrea.com>
Signed-off-by: Tom Rix <Tom.Rix@windriver.com>