V4L/DVB: gspca - gl860: new driver for MI2020 sensor

- new MI2020 driver version made from a webcam gift
- all previous flavors of this driver removed

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