usb: dwc3: Support option to disable USB2 LPM

Support the option to disable USB2 LPM. Set xhci "usb2-lpm-disable"
property via "snps,usb2-lpm-disable" property.

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/host.c

@@ -46,7 +46,7 @@ out:
 
 int dwc3_host_init(struct dwc3 *dwc)
 {
-	struct property_entry	props[3];
+	struct property_entry	props[4];
 	struct platform_device	*xhci;
 	int			ret, irq;
 	struct resource		*res;
@@ -93,6 +93,9 @@ int dwc3_host_init(struct dwc3 *dwc)
 	if (dwc->usb3_lpm_capable)
 		props[prop_idx++].name = "usb3-lpm-capable";
 
+	if (dwc->usb2_lpm_disable)
+		props[prop_idx++].name = "usb2-lpm-disable";
+
 	/**
 	 * WORKAROUND: dwc3 revisions <=3.00a have a limitation
 	 * where Port Disable command doesn't work.