driver core: platform: fix race condition with driver_override

The driver_override implementation is susceptible to race condition when
different threads are reading vs storing a different driver override.
Add locking to avoid race condition.

Fixes: 3d713e0e382e ("driver core: platform: add device binding path 'driver_override'")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Salido <salidoa@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
static int platform_legacy_resume(struct device *dev)
{
	struct platform_driver *pdrv = to_platform_driver(dev->driver);
	struct platform_device *pdev = to_platform_device(dev);
	int ret = 0;

	if (dev->driver && pdrv->resume)
		ret = pdrv->resume(pdev);

	return ret;
}

static int platform_legacy_resume(struct device *dev)
{
	struct platform_driver *pdrv = to_platform_driver(dev->driver);
	struct platform_device *pdev = to_platform_device(dev);
	int ret = 0;

	if (dev->driver && pdrv->resume)
		ret = pdrv->resume(pdev);

	return ret;
}
