Config iomux-gpr1 to select clock source for fec system clock.
Clear gpr1[14], gpr1[18-17] bit to select the fec clock source
from internal anatop PLL.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>