V4L/DVB: cx25840: Add s_io_pin_config core subdev ops for the CX2388[578]

Add s_io_pin_config core subdev op for the CX2388[578] AV cores.
This is complete for IR_RX, IR_TX, GPIOs 16,19-23, and IRQ_N.
It likely needs work for the I2S signal direction.

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