Camera3: Ensure postprocessor is stopped during teardown

Not shutting down postprocessor during channel teardown
can cause jpeg messaging threads to linger around,
causing performance issue due to large number of abandoned
threads.

Bug: 19255187
Change-Id: Icde28a91ccc80bb29b836588abfdfca94ae97d27

camera/QCamera2/HAL3/QCamera3Channel.cpp

@@ -927,7 +927,11 @@ QCamera3PicChannel::QCamera3PicChannel(uint32_t cam_handle,
 
 QCamera3PicChannel::~QCamera3PicChannel()
 {
-    int32_t rc = m_postprocessor.deinit();
+    int32_t rc = m_postprocessor.stop();
+    if (rc != NO_ERROR) {
+        ALOGE("%s: Postprocessor stop failed", __func__);
+    }
+    rc = m_postprocessor.deinit();
     if (rc != 0) {
         ALOGE("De-init Postprocessor failed");
     }