usb: dwc3: gadget: Fix dead code writing GCTL.RAMCLKSEL

The register programming code in dwc2_updated_ram_clk_sel() will never
be executed. And in fact the entire function can be removed as there is
no way to override the default value of GCTL.RAMCLKSEL. Remove the
function and add a comment explaining where GCTL.RAMCLKSEL should be
programmed if needed in the future.

This fixes dead code warnings in coverity.
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/gadget.c

@@ -2468,32 +2468,6 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
 	dwc3_writel(dwc->regs, DWC3_DCFG, reg);
 }
 
-static void dwc3_update_ram_clk_sel(struct dwc3 *dwc, u32 speed)
-{
-	u32 reg;
-	u32 usb30_clock = DWC3_GCTL_CLK_BUS;
-
-	/*
-	 * We change the clock only at SS but I dunno why I would want to do
-	 * this. Maybe it becomes part of the power saving plan.
-	 */
-
-	if ((speed != DWC3_DSTS_SUPERSPEED) &&
-	    (speed != DWC3_DSTS_SUPERSPEED_PLUS))
-		return;
-
-	/*
-	 * RAMClkSel is reset to 0 after USB reset, so it must be reprogrammed
-	 * each time on Connect Done.
-	 */
-	if (!usb30_clock)
-		return;
-
-	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
-	reg |= DWC3_GCTL_RAMCLKSEL(usb30_clock);
-	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
-}
-
 static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc)
 {
 	struct dwc3_ep		*dep;
@@ -2505,7 +2479,14 @@ static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc)
 	speed = reg & DWC3_DSTS_CONNECTSPD;
 	dwc->speed = speed;
 
-	dwc3_update_ram_clk_sel(dwc, speed);
+	/*
+	 * RAMClkSel is reset to 0 after USB reset, so it must be reprogrammed
+	 * each time on Connect Done.
+	 *
+	 * Currently we always use the reset value. If any platform
+	 * wants to set this to a different value, we need to add a
+	 * setting and update GCTL.RAMCLKSEL here.
+	 */
 
 	switch (speed) {
 	case DWC3_DSTS_SUPERSPEED_PLUS: