[media] redrat3: new rc-core IR transceiver device driver

[media] redrat3: new rc-core IR transceiver device driver

This is a new rc-core device driver for the IR transceivers made by
RedRat Ltd. (http://redrat.co.uk/). It started out life as an
out-of-lirc-tree lirc driver, maintained in its own repo on sourceforge,
by Stephen Cox. He started porting it to what was then ir-core, and I
finally picked it up about two week ago and did a fairly large overhaul
on it, and its now into a state where I'm fairly comfortable submitting
it here for review and inclusion in the kernel. I'm claiming authorship
of this driver, since while it started out as Stephen's work, its
definitely a derivative work now, at 876 lines added and 1698 lines
removed since grabbing it from sourceforge. Stephen's name is retained
as secondary author though, and credited in the headers. Those
interested in seeing how the changes evolved can (at least for now) look
at this branch in my git tree:

http://git.kernel.org/?p=linux/kernel/git/jarod/linux-2.6-ir.git;a=shortlog;h=refs/heads/redrat3

That won't be around forever though, and I'm doing this as a single
commit to go into mainline. Anyway...

I've successfully tested in-kernel decode of rc5, rc6 and nec remotes,
as well as lirc userspace decode of rc5 and rc6. There are still some
quirks here to sort out with rc5 lirc userspace decode, but I'm working
with the RedRat folks themselves to figure out what's going on there
(rc5 lirc decode works, but you only get an event on key release --
in-kernel rc5 decode behaves perfectly fine). Note that lirc decode of
rc6 is working perfectly. Transmit is also working, tested by pointing
the redrat3 at an mceusb transceiver, which happily picked up the
transmitted signals and properly decoded them.

There's no default remote for this hardware, so its somewhat arbitrarily
set to use the Hauppauge RC5 keymap by default. Easily changed out by
way of ir-keytable and irrelevant if you're using lircd for decode.

CC: Chris Dodge <chris@redrat.co.uk>
CC: Andrew Vincer <Andrew.Vincer@redrat.co.uk>
CC: Stephen Cox <scox_nz@yahoo.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>