fec: Invert the order of error path sequence

Currently when fec_enet_init fails it jumps to 'failed_init' error path, which
will attemp to free the interrupts.

This is wrong because at this point the interrupts have not even been acquired.

Swap failed_init/failed_irq to fix the error path.

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