net: ethernet: ax88796: don't call free_irq without request_irq first

The function ax_init_dev (which is called only from the driver's .probe
function) calls free_irq in the error path without having requested the
irq in the first place. So drop the free_irq call in the error path.

Fixes: 825a2ff1

 ("AX88796 network driver")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>