fec: Remove irqs first

During probe the clocks are enabled prior than the acquiring the interrupts.

In the remove function we need to do the opposite: first remove the interrupts
and then disable the clocks.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>