usb: dwc2: host: fix the data toggle error in full speed descriptor dma

There will be data toggle error happen for full speed buld-out transfer.
The data toggle bit is saved in qh for non-control transfers, it is wrong
to  check the qtd for that case.

Also fix one static analysis tool issue after fix the data toggle error.

John Youn:
* Added WARN() to warn on improper usage of the
  dwc2_hcd_save_data_toggle() function.

Signed-off-by: Dyson Lee <dyson.lee@intel.com>
Signed-off-by: Tang, Jianqiang <jianqiang.tang@intel.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/dwc2/hcd_ddma.c

@@ -1257,7 +1257,7 @@ stop_scan:
 		 */
 		if (halt_status == DWC2_HC_XFER_STALL)
 			qh->data_toggle = DWC2_HC_PID_DATA0;
-		else if (qtd)
+		else
 			dwc2_hcd_save_data_toggle(hsotg, chan, chnum, qtd);
 	}
 

drivers/usb/dwc2/hcd_intr.c

@@ -525,11 +525,19 @@ void dwc2_hcd_save_data_toggle(struct dwc2_hsotg *hsotg,
 	u32 pid = (hctsiz & TSIZ_SC_MC_PID_MASK) >> TSIZ_SC_MC_PID_SHIFT;
 
 	if (chan->ep_type != USB_ENDPOINT_XFER_CONTROL) {
+		if (WARN(!chan || !chan->qh,
+			 "chan->qh must be specified for non-control eps\n"))
+			return;
+
 		if (pid == TSIZ_SC_MC_PID_DATA0)
 			chan->qh->data_toggle = DWC2_HC_PID_DATA0;
 		else
 			chan->qh->data_toggle = DWC2_HC_PID_DATA1;
 	} else {
+		if (WARN(!qtd,
+			 "qtd must be specified for control eps\n"))
+			return;
+
 		if (pid == TSIZ_SC_MC_PID_DATA0)
 			qtd->data_toggle = DWC2_HC_PID_DATA0;
 		else