1. remove the feature mask parameter from AVRC connection state event, as the AVCTP connection can be initiated by remote device before service discovery to remote device is performed. \
In this case, AVRCP connection state event may not be reported after connection initated by remote device is established.
2. remove ESP_AVRC_CT_MAX_EVT
3. add more documentations to AVRC APIs
1. fix the bug. Modify the condition that esp_bt_controller_mem_release() shoud be only called before esp_bt_controller_init() or after esp_bt_controller_deinit()
2. modify the example to use esp_bt_controller_mem_release()
NVS is used to store PHY calibration data, WiFi configuration, and BT
configuration. Previously BT examples did not call nvs_flash_init,
relying on the fact that it is called during PHY init. However PHY init
did not handle possible NVS initialization errors.
This change moves PHY init procedure into the application, and adds
diagnostic messages to BT config management routines if NVS is not
initialized.
