mt76: mt7663: check isr read return value in mt7663s_rx_work

In order to avoid using stale isr values, check return value from
sdio_readsb() in mt7663s_rx_work()
Tested-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7615/sdio_txrx.c

@@ -278,9 +278,12 @@ void mt7663s_rx_work(struct work_struct *work)
 	/* disable interrupt */
 	sdio_claim_host(sdio->func);
 	sdio_writel(sdio->func, WHLPCR_INT_EN_CLR, MCR_WHLPCR, NULL);
-	sdio_readsb(sdio->func, intr, MCR_WHISR, sizeof(struct mt76s_intr));
+	ret = sdio_readsb(sdio->func, intr, MCR_WHISR, sizeof(*intr));
 	sdio_release_host(sdio->func);
 
+	if (ret < 0)
+		goto out;
+
 	trace_dev_irq(dev, intr->isr, 0);
 
 	if (intr->isr & WHIER_RX0_DONE_INT_EN) {
@@ -306,7 +309,7 @@ void mt7663s_rx_work(struct work_struct *work)
 		queue_work(sdio->txrx_wq, &sdio->rx.recv_work);
 		return;
 	}
-
+out:
 	/* enable interrupt */
 	sdio_claim_host(sdio->func);
 	sdio_writel(sdio->func, WHLPCR_INT_EN_SET, MCR_WHLPCR, NULL);