[media] IR: add driver for Nuvoton w836x7hg integrated CIR

[media] IR: add driver for Nuvoton w836x7hg integrated CIR

This is a new ir-core pnp driver for the Nuvoton w836x7hg integrated CIR
function. The chip is found on at least the ASRock ION 330HT boxes and
apparently, on a number of Intel DP55-series motherboards:

http://www.asrock.com/nettop/overview.asp?Model=ION%20330HT
http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=17685&lang=eng

This driver was made possible by a hardware donation from Nuvoton, along
with sample code (in the form of an lirc driver) and datasheet, so huge
thanks to them for supporting this effort. Note that this driver
constitutes a massive rewrite, porting from the lirc interfaces to the
ir-core interfaces, and restructuring the driver to look more like Maxim
Levitsky's ene_ir driver (as well as generally making it look more like
kernel code).

There's some work left to be done on this driver, to fully support the
range of functionality possible, but receive and IR power-on/wake are
both functional (may require setting wake key under another OS atm). The
hardware I've got (one of the ASRock boxes) only supports RX, so TX is
completely untested as of yet. Certain RX parameters, like sample
resolution and RX IRQ sample length trigger level could possibly stand
to be made tweakable via modparams or sysfs nodes, but the current
values work well enough for me w/an MCE RC6A remote.

The original lirc driver carried support for the Windows MCE IR
keyboard/mouse device, which I plan to add back generically, in a way
that should be usable by any raw IR receiver (or at least by this driver
and the mceusb driver).

Suspend and resume have also been tested, the power button on my remote
can be used to wake the machine, and CIR functionality resumes just
fine. Module unload/reload has also been tested, though not extensively
or repetitively. Also tested to work with the lirc bridge plugin for
userspace decoding.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>