[media] uvcvideo: Simplify redundant check

x < constant implies x + unsigned < constant
That check just obfuscates the code

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>