Revert "drivers/usb: Remove unnecessary return's from void functions" partially

This is a partial revert of 7f26b3a7 ("drivers/usb: Remove unnecessary
return's from void functions") as this hunk will go through USB tree
due to conflict.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

drivers/usb/gadget/langwell_udc.c

@@ -284,6 +284,7 @@ static void ep0_reset(struct langwell_udc *dev)
 	}
 
 	VDBG(dev, "<--- %s()\n", __func__);
+	return;
 }
 
 
@@ -1485,6 +1486,7 @@ static void langwell_udc_start(struct langwell_udc *dev)
 	writel(usbcmd, &dev->op_regs->usbcmd);
 
 	DBG(dev, "<--- %s()\n", __func__);
+	return;
 }
 
 
@@ -1507,6 +1509,7 @@ static void langwell_udc_stop(struct langwell_udc *dev)
 	writel(usbcmd, &dev->op_regs->usbcmd);
 
 	DBG(dev, "<--- %s()\n", __func__);
+	return;
 }