tinyalsa: add support for tinyalsa pcm plugins

Update the pcm framework to support plugins. Resolve the pcm device node
to be either kernel device or virtual device and setup function pointers
accordingly. Implement framework functionality for pcm plugin for ease
of plugin development.

CRs-Fixed: 2563258
Change-Id: I48ff23da6efc10e9e1bd137521883b8761fc96ba
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>
8 files changed