[media] em28xx: add MSI Digivox Trio support

Add support for the MSI Digivox Trio device.

Signed-off-by: P. van Gaans <w3ird_n3rd@gmx.net>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>