[ALSA] Fix conflicts between const and __devinitdata

Marvin told with a depressed face,
  gcc doesn't like both __devinitdata and const in the same line.
So, remove const from all over places now...

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