fix(nimble): Added code under correct flags

Code was not under correct flag. Hence if flag is disabled, then
compilation warnings are observed. Fixed the same

Based on PR : https://github.com/espressif/esp-nimble/pull/107

nimble/host/src/ble_hs.c

@@ -932,7 +932,7 @@ ble_hs_deinit(void)
 
     ble_npl_event_deinit(&ble_hs_ev_reset);
 
-#if NIMBLE_BLE_CONNECT
+#if NIMBLE_BLE_CONNECT && MYNEWT_VAL(BLE_GATTS)
     ble_npl_event_deinit(&ble_hs_ev_tx_notifications);
 
     ble_gatts_stop();