V4L/DVB: v4l2_subdev, cx23885: Differentiate IR carrier sense and I/O pin inversion

There is a distinction on IR Tx for the CX2388[578] chips of carrier
sense inversion (space is a carrier burst and mark is no burst) and I/O
pin level inversion (0 is high output level, 1 is low output level).
Allow the caller to set these parameters distinctly as v4l2_subdevice
IR parameters.  This permits the IR device to be configured and enabled
without the IR Tx LED being on during idle/space time due to an external
hardware level inversion

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