V4L/DVB (11491): af9015: support for AverMedia AVerTV Volar GPS 805 (A805)

Add USB ID (07ca:a805) for AverMedia AVerTV Volar GPS 805 (A805).
Thanks to Chris Brown <chrisneilbrown@gmail.com> for reporting and
testing.

Tested-by: Chris Brown <chrisneilbrown@gmail.com>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>