V4L/DVB: gspca_cpia1: Disable illuminator controls if not an Intel Play QX3

The illuminator controls should only be available to the user for the Intel
Play QX3 microscope.  The implementation to inhibit the controls is intended to
be consistent with the other gspca driver implementations.

Signed-off-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>