HID: usbhid: Simplify code in hid_submit_ctrl()

This patch makes a small simplification to the code in
hid_submit_ctrl().  The test for maxpacket being > 0 is unnecessary,
because endpoint 0 always has a maxpacket value which is >= 8.

Furthermore, endpoint 0's maxpacket value is always a power of 2, so
instead of open-coding the round-to-next-multiple computation we can
call the optimized round_up() routine.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/usbhid/hid-core.c

@@ -388,14 +388,10 @@ static int hid_submit_ctrl(struct hid_device *hid)
 		usbhid->urbctrl->pipe = usb_rcvctrlpipe(hid_to_usb_dev(hid), 0);
 		maxpacket = usb_maxpacket(hid_to_usb_dev(hid),
 					  usbhid->urbctrl->pipe, 0);
-		if (maxpacket > 0) {
+		len += (len == 0);	/* Don't allow 0-length reports */
-			len += (len == 0);    /* Don't allow 0-length reports */
+		len = round_up(len, maxpacket);
-			len = DIV_ROUND_UP(len, maxpacket);
+		if (len > usbhid->bufsize)
-			len *= maxpacket;
+			len = usbhid->bufsize;
-			if (len > usbhid->bufsize)
-				len = usbhid->bufsize;
-		} else
-			len = 0;
 	}
 	usbhid->urbctrl->transfer_buffer_length = len;
 	usbhid->urbctrl->dev = hid_to_usb_dev(hid);