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

This is a partial revert of 7f26b3a7533b ("drivers/usb: Remove unnecessary
return's from void functions") as this hunk will go through USB tree
due to conflict.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/usb/gadget/langwell_udc.c b/drivers/usb/gadget/langwell_udc.c
index d41b69c..c2d2a20 100644
--- a/drivers/usb/gadget/langwell_udc.c
+++ b/drivers/usb/gadget/langwell_udc.c
@@ -284,6 +284,7 @@
 	}
 
 	VDBG(dev, "<--- %s()\n", __func__);
+	return;
 }
 
 
@@ -1485,6 +1486,7 @@
 	writel(usbcmd, &dev->op_regs->usbcmd);
 
 	DBG(dev, "<--- %s()\n", __func__);
+	return;
 }
 
 
@@ -1507,6 +1509,7 @@
 	writel(usbcmd, &dev->op_regs->usbcmd);
 
 	DBG(dev, "<--- %s()\n", __func__);
+	return;
 }