cx25840: fix probing of cx2583x chips

commit 1e6406b8f0dc1ae7d7c39c9e1ac6ca78e016ebfb upstream.

Fix the probing of cx2583x chips, because two controls were clustered
that are not created for these chips.

This regression was introduced in 2.6.36.

Signed-off-by: Sven Barth <pascaldragon@googlemail.com>
Signed-off-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>