ASoC: fsl_xcvr: check return value after calling platform_get_resource_byname()

It will cause null-ptr-deref if platform_get_resource_byname() returns NULL,
we need check the return value.
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20210615013922.784296-10-yangyingliang@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl_xcvr.c

@@ -1202,6 +1202,10 @@ static int fsl_xcvr_probe(struct platform_device *pdev)
 
 	rx_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rxfifo");
 	tx_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "txfifo");
+	if (!rx_res || !tx_res) {
+		dev_err(dev, "could not find rxfifo or txfifo resource\n");
+		return -EINVAL;
+	}
 	xcvr->dma_prms_rx.chan_name = "rx";
 	xcvr->dma_prms_tx.chan_name = "tx";
 	xcvr->dma_prms_rx.addr = rx_res->start;