at86rf230: add missing enable_irq

This patch adds a missing enable_irq when spi_async in isr failed.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/net/ieee802154/at86rf230.c

@@ -911,6 +911,7 @@ static irqreturn_t at86rf230_isr(int irq, void *data)
 	ctx->msg.complete = at86rf230_irq_status;
 	rc = spi_async(lp->spi, &ctx->msg);
 	if (rc) {
+		enable_irq(irq);
 		at86rf230_async_error(lp, ctx, rc);
 		return IRQ_NONE;
 	}