V4L/DVB: arv: convert to V4L2

Converted this old V4L1 driver to V4L2.
I would like to thank Takeo Takahashi who very kindly tested this
driver for me. Much appreciated!

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Tested-by: Takeo Takahashi <takahashi.takeo@renesas.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>