at86rf230: fix context pointer handling

This patch changes the context pointer to the parameter given one inside
function at86rf230_async_state_change_start. This could occur problem if
context isn't pointed to lp->state.
Signed-off-by: NAlexander Aring <alex.aring@gmail.com>
Reviewed-by: NStefan Schmidt <s.schmidt@samsung.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

drivers/net/ieee802154/at86rf230.c

@@ -654,7 +654,7 @@ at86rf230_async_state_change_start(void *context)
 		if (ctx->irq_enable)
 			enable_irq(lp->spi->irq);
 
-		at86rf230_async_error(lp, &lp->state, rc);
+		at86rf230_async_error(lp, ctx, rc);
 	}
 }