alsa: determine signal precision
alsa: determine signal precision

Use snd_pcm_hw_params_get_sbits() to ask the driver for the number of
significant bits, which may differ from the encoding size.

davel/sox,cbagwell/sox,pcqpcq/sox,Distrotech/sox,Motiejus/sox,Distrotech/sox,jacksonh/sox,MageSlayer/sox,mhartzel/sox_personal_fork,mhartzel/sox_personal_fork,uklauer/sox,cbagwell/sox,CaptainHayashi/sox,MageSlayer/sox,MageSlayer/sox,pcqpcq/sox,Motiejus/sox,jacksonh/sox,cbagwell/sox,uklauer/sox,cbagwell/sox,CaptainHayashi/sox,Motiejus/sox,uklauer/sox,mhartzel/sox_personal_fork,davel/sox,mhartzel/sox_personal_fork,jacksonh/sox,jacksonh/sox,MageSlayer/sox,davel/sox,uklauer/sox,Motiejus/sox,Distrotech/sox,CaptainHayashi/sox,pcqpcq/sox,MageSlayer/sox,pcqpcq/sox,Distrotech/sox,CaptainHayashi/sox,davel/sox