libstagefright: Enable suspension policy

- ADSP doesn't enter suspend state after audio playback.
- No support for suspension policy in stagefright.
- Enable suspension policy in stagefright to allow
  component to move into suspend mode.

CRs-fixed: 386381
(cherry picked from commit 735bc83e32e64af25a6163c07e2039eb4354ff00)

Change-Id: If32bfc63bbb25563e14b128712cc90639b15dc5b
Signed-off-by: Ramakrishna Prasad N <crpn@codeaurora.org>