powerpc/fs_enet: Add missing irq free in error path.

If something goes wrong attaching to phy driver, we weren't freeing
the IRQ.
Signed-off-by: Mike Ditto <mditto@consentry.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/fs_enet/fs_enet-main.c

@@ -795,6 +795,7 @@ static int fs_enet_open(struct net_device *dev)
 
 	err = fs_init_phy(dev);
 	if (err) {
+		free_irq(fep->interrupt, dev);
 		if (fep->fpi->use_napi)
 			napi_disable(&fep->napi);
 		return err;