ALSA: ALS4000 driver work, step 2

ALSA: ALS4000 driver work, step 2

- more register naming work
- finally figured out that weird CR register stuff
  (and did I mention that I hate _really_ undecipherable open-coded values?)
- fix handling of IRQ sharing in interrupt handler
  (hopefully properly, otherwise I'd be grateful to hear your
  pedantic comments ;)
- add handy SPECS_PAGE references wherever useful
- comments, cleanup
- add me as module author

Signed-off-by: Andreas Mohr <andi@lisas.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>