alsa-gobject: supplement to use guint8 for the numerical ID of client/queue

alsa-project/alsa-gobject pull request #42 was edited from takaswie:

Some APIs are missing in #41. This patchset has supplements for them.

Request URL : https://github.com/alsa-project/alsa-gobject/pull/42 Patch URL : https://github.com/alsa-project/alsa-gobject/pull/42.patch Repository URL: https://github.com/alsa-project/alsa-gobject