refence to https://github.com/espressif/esp-idf/issues/2284
Before fixing, the tx power in adv data is always 0xeb(-21dbm).
restriction:
If change BLE advertising TX power, please call esp_ble_gap_config_adv_data()
after BLE adv TX power changed.
Later, will implement set BLE advertising TX power via HCI, then the
TX power value in adv data can be update automatically after BLE adv
TX power changed.