This patch adds FEC support for Vybrid VF610 platform.

In function fec_open(), RCR register is only set as RGMII mode. But RCR
register should be set as RMII mode for VF610 platform.
This configuration is already done in fec_reg_setup(), so this piece of
code could just leave untouched the FEC_RCNTRL_RGMII / FEC_RCNTRL_RMII /
FEC_RCNTRL_MII_MODE bits.

Signed-off-by: Alison Wang <b18965@freescale.com>
Reviewed-by: Benoit Thebaudeau <benoit.thebaudeau@advansee.com>
Reviewed-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>