usb: dwc3: gadget: only resume USB2 PHY in <=HIGHSPEED

As a micro-power optimization, let's only resume the
USB2 PHY if we're working on <=HIGHSPEED. If we're
gonna work on SUPERSPEED or SUPERSPEED+, there's no
point in resuming the USB2 PHY.

Fixes: 2b0f11df84bb ("usb: dwc3: gadget: clear SUSPHY bit before ep cmds")
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/gadget.c

@@ -258,11 +258,13 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned cmd,
 	 * We will also set SUSPHY bit to what it was before returning as stated
 	 * by the same section on Synopsys databook.
 	 */
-	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
-	if (unlikely(reg & DWC3_GUSB2PHYCFG_SUSPHY)) {
-		susphy = true;
-		reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
-		dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
+	if (dwc->gadget.speed <= USB_SPEED_HIGH) {
+		reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
+		if (unlikely(reg & DWC3_GUSB2PHYCFG_SUSPHY)) {
+			susphy = true;
+			reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
+			dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
+		}
 	}
 
 	if (cmd == DWC3_DEPCMD_STARTTRANSFER) {