platform/x86: intel_punit_ipc: Avoid error message when retrieving IRQ

Since the commit

  7723f4c5 ("driver core: platform: Add an error message to platform_get_irq*()")

the platform_get_irq() started issuing an error message which is not
what we want here.

Switch to platform_get_irq_optional() to have only warning message
provided by the driver.

Fixes: 7723f4c5 ("driver core: platform: Add an error message to platform_get_irq*()")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/intel_punit_ipc.c

@@ -293,9 +293,8 @@ static int intel_punit_ipc_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, punit_ipcdev);
 
-	irq = platform_get_irq(pdev, 0);
+	irq = platform_get_irq_optional(pdev, 0);
 	if (irq < 0) {
-		punit_ipcdev->irq = 0;
 		dev_warn(&pdev->dev, "Invalid IRQ, using polling mode\n");
 	} else {
 		ret = devm_request_irq(&pdev->dev, irq, intel_punit_ioc,