spi: hisi-sfc-v3xx: fix potential irq race condition

We mask the irq when the command completion is timeout. This won't
stop the already running irq handler. Use sychronize_irq() after
we mask the irq, to make sure there is no running handler.
Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/1618228708-37949-2-git-send-email-yangyicong@hisilicon.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-hisi-sfc-v3xx.c

@@ -342,6 +342,7 @@ static int hisi_sfc_v3xx_generic_exec_op(struct hisi_sfc_v3xx_host *host,
 			ret = 0;
 
 		hisi_sfc_v3xx_disable_int(host);
+		synchronize_irq(host->irq);
 		host->completion = NULL;
 	} else {
 		ret = hisi_sfc_v3xx_wait_cmd_idle(host);