usb: dwc3: core: Fix broken system suspend/resume on AM437x

On TI's AM437x, the DWC3 controller looses state after a
system suspend/resume. We are re-initializing the controller
but we miss restoring the PRTCAP register. This causes
USB host to break on AM437x after a system suspend/resume.

Fix this by restoring the PRTCAP register on system resume.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/core.c

@@ -1440,6 +1440,7 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
 		if (ret)
 			return ret;
 
+		dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_DEVICE);
 		spin_lock_irqsave(&dwc->lock, flags);
 		dwc3_gadget_resume(dwc);
 		spin_unlock_irqrestore(&dwc->lock, flags);
@@ -1450,6 +1451,7 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
 			ret = dwc3_core_init(dwc);
 			if (ret)
 				return ret;
+			dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_HOST);
 		}
 		break;
 	case DWC3_GCTL_PRTCAP_OTG: