[media] usbvision: add missing USB-descriptor endianness conversions

Add the missing endianness conversions to a debug call printing the
USB device-descriptor idVendor and idProduct fields during probe.

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>