V4L/DVB (13181): gspca w9968cf: Add support for JPEG compression

gspca w9968cf: Add support for JPEG compression, this enables much higher
framerates at 320x240 / 352x288 and also allows for 640x480 mode for
cams which can do this. The w9968cf uses planar JPEG, which libv4l until
now did not support, so this requires atleast version 0.6.3 of libv4l.

And something important I forgot to mention in my earlier w9968cf commits:
Many thanks to Hans Verkuil for giving me a w9968cf based cam, which has
allowed me to develop the gspca w9968cf support.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>