usb: dwc3: of-simple: set dev_pm_ops

dwc3_of_simple_dev_pm_ops has never been used since the initial support
by commit 16adc674 ("usb: dwc3: add generic OF glue layer").

I guess it just missed to set .pm struct member.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/dwc3-of-simple.c

@@ -205,6 +205,7 @@ static struct platform_driver dwc3_of_simple_driver = {
 	.driver		= {
 		.name	= "dwc3-of-simple",
 		.of_match_table = of_dwc3_simple_match,
+		.pm	= &dwc3_of_simple_dev_pm_ops,
 	},
 };