Load the TWS+ devices when TWS+ service is available.

Loading TWS+ devices before TWS+devices are available
TWS+ would not be configured. So this change would take
care of loading the TWS+ devices when TWS+ service is
available.

Change-Id: I3b699e8ee8f2cba574ca3194572030dc8e8ce757
diff --git a/system_bt_ext/btif/src/btif_tws_plus.cc b/system_bt_ext/btif/src/btif_tws_plus.cc
index af3d010..b030604 100644
--- a/system_bt_ext/btif/src/btif_tws_plus.cc
+++ b/system_bt_ext/btif/src/btif_tws_plus.cc
@@ -469,6 +469,7 @@
   if (twsplus_enabled == true) {
     if (b_enable) {
       BTA_TwsPlusEnable(btif_tws_plus_callback);
+      btif_tws_plus_load_tws_devices();
     } else {
       BTA_TwsPlusDisable();
     }