at86rf230: add missing error handling

This patch adds an async error handling function if sync state change
runs into a timeout. The async error handling function tries to recover
the phy state machine into a valid state.
Signed-off-by: NAlexander Aring <alex.aring@gmail.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

drivers/net/ieee802154/at86rf230.c

@@ -690,8 +690,10 @@ at86rf230_sync_state_change(struct at86rf230_local *lp, unsigned int state)
 
 	rc = wait_for_completion_timeout(&lp->state_complete,
 					 msecs_to_jiffies(100));
-	if (!rc)
+	if (!rc) {
+		at86rf230_async_error(lp, &lp->state, -ETIMEDOUT);
 		return -ETIMEDOUT;
+	}
 
 	return 0;
 }