settings: update control ring stream string

    <string name="volbtn_cursor_control_on_reverse">Volume up/down moves cursor right/left</string>

    <string name="swap_volume_buttons_title">Reorient</string>

    <string name="swap_volume_buttons_summary">Swap volume buttons when the screen is rotated</string>

    <string name="volume_keys_control_ring_stream_title">Control ringtone</string>

    <string name="volume_keys_control_ring_stream_title">Control ringtone volume</string>

    <string name="volume_keys_control_ring_stream_summary_on">Volume keys control ringtone volume</string>

    <string name="volume_keys_control_ring_stream_summary_off">Volume keys control media volume</string>

    <string name="power_end_call_title">End call</string>