net: fec: pass ->dev to dma_alloc__coherent() API

In aarch64 system, it requires to trasfer ->dev to dma_alloc_coherent()
API, otherwise allocate failed and print kernel warning.

Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>