V4L/DVB: cx2341x: Remove temporal filter control restriction

Since the change that stops the CX23415/6 firmware-intiiated secondary stream
appears to fix the temporal filter, it's now fully re-enabled for all capture
resolutions.

Signed-off-by: Ian Armstrong <ian@iarmst.demon.co.uk>
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>