A simple conversion from a text file.

A new subidrectory, Documentation/sound/designs, was created to put
this document.  The other API design and implementation docuemnts
will be put to that directory in later commits.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

A simple conversion from the text file.

Since this is the only document specific to the configurations, it's
put to the root sound subdirectory.

A section describing the obsoleted configure stuff of old alsa-driver
tarball got removed.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The original HD-Audio.txt was already in asciidoc format, so it's a
simple conversion in the end.

A new subdirectory, Documentation/sound/hd-audio, is created and the
document is moved there with another file name to match better with
the recent Documentation tree structure.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

A simple conversion of alsa-driver-api document from DocBook to ReST.

It's moved to the new Documentation/sound/kernel-api subdirectory that
will contain other ALSA kernel API documents.

The GPL legal note was removed, as it's superfluous (and doesn't fit
with ReST kernel docs pretty well).
Signed-off-by: NTakashi Iwai <tiwai@suse.de>