USB: ipaq.c: fix a timeout loop

The code expects the loop to end with "retries" set to zero but, because
it is a post-op, it will end set to -1.  I have fixed this by moving the
decrement inside the loop.

Fixes: 014aa2a3 ('USB: ipaq: minor ipaq_open() cleanup.')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/ipaq.c

@@ -531,7 +531,8 @@ static int ipaq_open(struct tty_struct *tty,
 	 * through. Since this has a reasonably high failure rate, we retry
 	 * several times.
 	 */
-	while (retries--) {
+	while (retries) {
+		retries--;
 		result = usb_control_msg(serial->dev,
 				usb_sndctrlpipe(serial->dev, 0), 0x22, 0x21,
 				0x1, 0, NULL, 0, 100);