Dynamically configure the number of video buffers used by camera source, if supported

o related-to-bug: 6920805

Change-Id: I413bb50954cc84e32ed40bcb713842dc7b58e2b6
diff --git a/services/camera/libcameraservice/CameraClient.cpp b/services/camera/libcameraservice/CameraClient.cpp
index 54829ef..562384d 100644
--- a/services/camera/libcameraservice/CameraClient.cpp
+++ b/services/camera/libcameraservice/CameraClient.cpp
@@ -619,6 +619,9 @@
         return OK;
     } else if (cmd == CAMERA_CMD_PLAY_RECORDING_SOUND) {
         mCameraService->playSound(CameraService::SOUND_RECORDING);
+    } else if (cmd == CAMERA_CMD_SET_VIDEO_BUFFER_COUNT) {
+        // Silently ignore this command
+        return INVALID_OPERATION;
     } else if (cmd == CAMERA_CMD_PING) {
         // If mHardware is 0, checkPidAndHardware will return error.
         return OK;