V4L/DVB: cx23885: For CX23888 IR, configure the IO pin mux IR pins explcitly

Explicitly configure the IR Tx and IR Rx pins to be driven by the
IR Rx and Tx pads from the AV core for CX23888 IR.

For the HVR-1850 and HVR-1290 configure the IR Tx level inversion,
so the Tx LED is off when idle.

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