Adds lookup table for floating point decibel volume, and new functions
to allow for setting the decibel level on the DSP.
Signed-off-by: NConnor McAdams <conmanx360@gmail.com>
Reviewed-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>