ASoC: dwc: Get IRQ optionally

The IRQ is explicitly optional, so use platform_get_irq_optional() and
avoid platform_get_irq() logging a spurious error when trying to use the
thing in DMA mode.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/c857f334e3c9e651e088b675b3938cb5f798b133.1629906123.git.robin.murphy@arm.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/dwc/dwc-i2s.c

@@ -642,7 +642,7 @@ static int dw_i2s_probe(struct platform_device *pdev)
 
 	dev->dev = &pdev->dev;
 
-	irq = platform_get_irq(pdev, 0);
+	irq = platform_get_irq_optional(pdev, 0);
 	if (irq >= 0) {
 		ret = devm_request_irq(&pdev->dev, irq, i2s_irq_handler, 0,
 				pdev->name, dev);