V4L/DVB: cx23885: Require user to explicitly enable CX2388[57] IR via module param

The CX23885 IR controller was reported to cause an interrupt storm
on a TeVii S470 card, but was reported fine on an HVR-1250.  Keep
integrated IR disabled by default on CX2388[57] based cards to avoid
a bad user experience in the general case.

Signed-off-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>