audiohal: Fix stream gc runner thread. [1/1]

PD#TV-27905

Problem:
The garbage collection thread running flag is
not initialized, causing the thread exits and
not functional.

Solution:
Add initialization of the thread running flag.

Verify:
Verified with Firebolt build on AB301.

Change-Id: I8bd418a5779ee0ba070185286192af405425bc58
Signed-off-by: Tim Yao <tim.yao@amlogic.com>
diff --git a/src/audio_server.cpp b/src/audio_server.cpp
index f41fff8..cfc36bf 100644
--- a/src/audio_server.cpp
+++ b/src/audio_server.cpp
@@ -82,6 +82,7 @@
   public:
     explicit AudioServiceImpl()
       : shm_(audio_server_shmem::getInstance(true)),
+        gc_runner_stop_(false),
         gc_runner_(std::thread([this] {
           while (!gc_runner_stop_) {
             streamout_gc_();