[ALSA] Single variables for cs5535audio

As per Takashi's feedback, this is a cleanup to make cs5535audio be
single device per system. The diff is against 2.6.17-rc4 with
Takashi's patch adding the module_params for index, id and enable.

Signed-off-by: Jaya Kumar <jayakumar.alsa@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>