sfos: bluez5: Use volume control in native backend.

Signed-off-by: Juho Hämäläinen <juho.hamalainen@jolla.com>

src/modules/bluetooth/backend-native.c

@@ -212,13 +212,17 @@ static int sco_acquire_cb(pa_bluetooth_transport *t, bool optional, size_t *imtu
         }
     }
 
+    pa_bluetooth_droid_volume_control_acquire(t->device->discovery, t);
+
     return sock;
 
 fail:
     return -1;
 }
 
 static void sco_release_cb(pa_bluetooth_transport *t) {
+    pa_bluetooth_droid_volume_control_release(t->device->discovery);
+
     pa_log_info("Transport %s released", t->path);
     /* device will close the SCO socket for us */
 }
@@ -423,6 +427,8 @@ static void rfcomm_io_callback(pa_mainloop_api *io, pa_io_event *e, int fd, pa_i
 static void transport_destroy(pa_bluetooth_transport *t) {
     struct transport_data *trd = t->userdata;
 
+    pa_bluetooth_droid_volume_control_release(t->device->discovery);
+
     if (trd->sco_io) {
         trd->mainloop->io_free(trd->sco_io);
         shutdown(trd->sco_fd, SHUT_RDWR);