fix(nimble): Add support for minimilistic builds

examples/bluetooth/nimble/power_save/main/main.c

@@ -623,9 +623,11 @@ app_main(void)
     rc = gatt_svr_init();
     assert(rc == 0);
 
+#if CONFIG_BT_NIMBLE_GAP_SERVICE
     /* Set the default device name. */
     rc = ble_svc_gap_device_name_set("nimble-bleprph");
     assert(rc == 0);
+#endif
 
     /* XXX Need to have template for store */
     ble_store_config_init();