SoundTrigger: get service by value.

Get strong pointer to service interface by value and not reference to
prevent race conditions where the service pointer can be cleared
by another thread while in use.

Bug: 30907212
Change-Id: I6f02ec3fd1e6392b842b334e1cc4f9aa23916009
(cherry picked from commit 3b01b3019b1c62132792a1a94e2dc1f7cfc84f2e)
2 files changed