at86rf230: fix race condition

When the driver waits for a tx completion currently the driver direct
enables the irq. When we switching to RX_AACK_ON some steps afterwards
the driver could receive a new frame and request resources which are
already in use, for example irq state change resource.

To be sure there are no new interrupts when we switching to RX_AACK_ON,
we enable the irq when state change to RX_AACK_ON was completed.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/net/ieee802154/at86rf230.c

@@ -705,6 +705,7 @@ at86rf230_tx_complete(void *context)
 	struct at86rf230_state_change *ctx = context;
 	struct at86rf230_local *lp = ctx->lp;
 
+	enable_irq(lp->spi->irq);
 	complete(&lp->tx_complete);
 }
 
@@ -860,7 +861,6 @@ at86rf230_irq_trx_end(struct at86rf230_local *lp)
 	if (lp->is_tx) {
 		lp->is_tx = 0;
 		spin_unlock(&lp->lock);
-		enable_irq(lp->spi->irq);
 
 		if (lp->tx_aret)
 			return at86rf230_async_state_change(lp, &lp->irq,