V4L/DVB (13196): gspca - gl860: add flip/mirror for OV2640

- add flip/mirror support for OV2640
- fix for backlight value range
- fix for red-blue inversion hue mode with V4L1 applications

Signed-off-by: Olivier Lorin <o.lorin@laposte.net>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>