ALSA: azt3328: large codec cleanup, add I2S port etc.

- fully separate codec I/O port handling, enabling the use of a single
  function each for all codecs (playback, capture, I2S out)
- add a new separate pcm for I2S out port (UNTESTED, no I2S DAC
  available yet)
- switch gameport to low frequency while idle, to try to reduce noise/power
- improve snd_azf3328_codec_setdmaa() calculation
- minor variable type cleanup (u16, bool etc.)
- add some doc updates (help those lost Windows users, debug help, ...)

Note that due to the large cleanup aspect of the codec I/O change,
I was able to fit everything including all improvements into the
same binary size!! (a measly 10 bytes more or so)

This should now be the almost last patch to this driver
(minus some possible kernel clocksource patch and x86_64 fixes or so).
I just felt like taking a break from the usual stuff and wanted to
get this driver's structure finished, and it's rather clean now...

Tested, working and checkpatch.pl:ed on 2.6.30-rc5,
applies cleanly to 2.6.30 proper.

Signed-off-by: Andreas Mohr <[email protected]>
Signed-off-by: Takashi Iwai <[email protected]>