net: fec: do not access reserved register for i.MX6UL

The MIB RAM and FIFO receive start register does not exist on
i.MX6UL. Accessing these register will cause enet not work well.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Signed-off-by: Fugang Duan <B38611@freescale.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Stefano Babic <sbabic@denx.de>
1 file changed