at86rf230: use devm_request_irq

This patch replace request_irq with devm_request_irq. With
devm_request_irq we don't need to care about freeing the irq.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed