[media] vivi: don't set V4L2_CAP_DEVICE_CAPS for the device_caps field

V4L2_CAP_DEVICE_CAPS is valid for the capabilities field only as per
the spec.

Found with v4l2-compliance.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>