usb: dwc3: gadget: fix GCTL programming

ensure a few bits are cleared before enabling
what we need.

Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 1de4d3f..6c64c73 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1150,13 +1150,10 @@
 
 	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
 
-	/*
-	 * REVISIT: power down scale might be different
-	 * depending on PHY used, need to pass that via platform_data
-	 */
-	reg |= DWC3_GCTL_PWRDNSCALE(0x61a)
-		| DWC3_GCTL_PRTCAPDIR(DWC3_GCTL_PRTCAP_DEVICE);
+	reg &= ~DWC3_GCTL_SCALEDOWN(3);
+	reg &= ~DWC3_GCTL_PRTCAPDIR(DWC3_GCTL_PRTCAP_OTG);
 	reg &= ~DWC3_GCTL_DISSCRAMBLE;
+	reg |= DWC3_GCTL_PRTCAPDIR(DWC3_GCTL_PRTCAP_DEVICE);
 
 	/*
 	 * WORKAROUND: DWC3 revisions <1.90a have a bug