[ALSA] azt3328.c: small cleanup patch

- change 'PCM' mixer control (pre/post 3D) to 'PCM Output Route'
- improve snd_azf3328_debug_show_ports
- less aggressive module init message
- document Bass/Treble non-bug (prompted by user report - Thank You!!)
- add some items to card description
- add some I/O register documentation
- enhance copyright

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