usb: renesas_usbhs: Remove dummy runtime PM callbacks

Platform drivers don't need dummy runtime PM callbacks that just return
success in order to have runtime PM happening. This has changed since
following commits:

commit 05aa55dd ("PM / Runtime: Lenient generic runtime pm callbacks")
commit 543f2503 ("PM / platform_bus: Allow runtime PM by default")
commit 8b313a38 ("PM / Platform: Use generic runtime PM callbacks directly")
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
[shimoda: revise git commit description style]
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/renesas_usbhs/common.c

@@ -874,23 +874,9 @@ static int usbhsc_resume(struct device *dev)
 	return 0;
 }
 
-static int usbhsc_runtime_nop(struct device *dev)
-{
-	/* Runtime PM callback shared between ->runtime_suspend()
-	 * and ->runtime_resume(). Simply returns success.
-	 *
-	 * This driver re-initializes all registers after
-	 * pm_runtime_get_sync() anyway so there is no need
-	 * to save and restore registers here.
-	 */
-	return 0;
-}
-
 static const struct dev_pm_ops usbhsc_pm_ops = {
 	.suspend		= usbhsc_suspend,
 	.resume			= usbhsc_resume,
-	.runtime_suspend	= usbhsc_runtime_nop,
-	.runtime_resume		= usbhsc_runtime_nop,
 };
 
 static struct platform_driver renesas_usbhs_driver = {