usb: dwc3: Describe 'wakeup_work' field of struct dwc3_pci

Describe 'wakeup_work' field of struct dwc3_pci to avoid a warning:

drivers/usb/dwc3/dwc3-pci.c:59: warning: Function parameter or member 'wakeup_work' not described in 'dwc3_pci'
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/dwc3-pci.c

@@ -49,6 +49,7 @@
  * @pci: our link to PCI bus
  * @guid: _DSM GUID
  * @has_dsm_for_pm: true for devices which need to run _DSM on runtime PM
+ * @wakeup_work: work for asynchronous resume
  */
 struct dwc3_pci {
 	struct platform_device *dwc3;