Add wallclock timestamp API

snd_pcm_hw_params_supports_audio_wallclock_ts() and
snd_pcm_status_get_audio_htstamp() are added.

Bumped the PCM protocol version to 2.0.11.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Add PCM chmap support

Not fully tested, though...

Signed-off-by: Takashi Iwai <tiwai@suse.de>