media: gspca_kinect: cast sizeof to int for comparison

Comparing an int to a size, which is unsigned, causes the int to become
unsigned, giving the wrong result.  kinect_read returns the result of
usb_control_msg, which can return a negtive error code.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
int x;
expression e,e1;
identifier f;
@@

*x = f(...);
... when != x = e1
    when != if (x < 0 || ...) { ... return ...; }
*x < sizeof(e)
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/usb/gspca/kinect.c

@@ -163,7 +163,7 @@ static int send_cmd(struct gspca_dev *gspca_dev, uint16_t cmd, void *cmdbuf,
 		actual_len = kinect_read(udev, ibuf, 0x200);
 	} while (actual_len == 0);
 	gspca_dbg(gspca_dev, D_USBO, "Control reply: %d\n", actual_len);
-	if (actual_len < sizeof(*rhdr)) {
+	if (actual_len < (int)sizeof(*rhdr)) {
 		pr_err("send_cmd: Input control transfer failed (%d)\n",
 		       actual_len);
 		return actual_len < 0 ? actual_len : -EREMOTEIO;