skypiax: snd-dummy alsa driver, make it ready (need to be edited before compilation) for alsa-1.0.22 still works on 1.0.20 and compatible with old alsa versions

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@16837 d0543943-73ff-0310-b7d9-9358b9ac24b2