ALSA: n64: check return value after calling platform_get_resource()

It will cause null-ptr-deref if platform_get_resource() returns NULL,
we need check the return value.
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20210610124958.116142-1-yangyingliang@huawei.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/mips/snd-n64.c

@@ -338,6 +338,10 @@ static int __init n64audio_probe(struct platform_device *pdev)
 	strcpy(card->longname, "N64 Audio");
 
 	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!res) {
+		err = -EINVAL;
+		goto fail_dma_alloc;
+	}
 	if (devm_request_irq(&pdev->dev, res->start, n64audio_isr,
 				IRQF_SHARED, "N64 Audio", priv)) {
 		err = -EBUSY;