platform/x86: portwell-ec: Move watchdog device under correct platform hierarchy

Without explicitly setting a parent for the watchdog device, the device is
registered with a NULL parent. This causes device_add() (called internally
by devm_watchdog_register_device()) to register the device under
/sys/devices/virtual, since no parent is provided. The result is:

DEVPATH=/devices/virtual/watchdog/watchdog0

To fix this, assign &pdev->dev as the parent of the watchdog device before
calling devm_watchdog_register_device(). This ensures the device is
associated with the Portwell EC platform device and placed correctly in
sysfs as:

DEVPATH=/devices/platform/portwell-ec/watchdog/watchdog0

This aligns the device hierarchy with expectations and avoids misplacement
under the virtual class.

Fixes: 8357967 ("platform/x86: portwell-ec: Add GPIO and WDT driver for Portwell EC")
Signed-off-by: Ivan Hu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Ilpo Järvinen <[email protected]>
Signed-off-by: Ilpo Järvinen <[email protected]>

Author: Ivanhu5866

drivers/platform/x86/portwell-ec.c

@@ -236,6 +236,7 @@ static int pwec_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	ec_wdt_dev.parent = &pdev->dev;
 	ret = devm_watchdog_register_device(&pdev->dev, &ec_wdt_dev);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to register Portwell EC Watchdog\n");