[media] pt3: add support for Earthsoft PT3 ISDB-S/T receiver card

This patch adds support for PT3 PCIe cards.
PT3 has an FPGA PCIe bridge chip, a TC90522 demod chip and
a VA4M6JC2103 tuner module which contains two QM1D1C0042 chips for ISDB-S
and two MxL301RF's for ISDB-T.
It can receive and deliver 4 (2x ISDB-S, 2x ISDB-T) streams simultaneously,
and a kthread is used per stream to poll incoming data,
because PT3 does not have interrupts.

As an antenna input for each delivery system is split in the tuner module
and shared between the corresponding two tuner chips,
LNB/LNA controls that the FPGA chip provides are (naturally) shared as well.
The tuner chips also share the power line in the tuner module,
which is controlled on/off by a GPIO pin of the demod chip.

As with the demod chip and the ISDB-T tuner chip,
the init sequences/register settings for those chips are not disclosed
and stored in a private memory of the FPGA,
PT3 driver executes the init of those chips on behalf of their drivers.

Signed-off-by: Akihiro Tsukada <tskd08@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>