audio: Added fallback mechanism for Tunnel Mode

On L, checkTunnelExceptions always gets stream type as MUSIC
because AudioOutput gets the actual stream only after AudioTrack
is created. AwesomePlayer tries play MP3/AAC ringtones in tunnel
mode due to this reason. Also, AudioOutput fails to set the
actual stream type for tunnel case which results in MUSIC
and RINGTONE getting mixed

Added fallback mechasism for tunnel mode so that ring tones
are rejected by the tunnel player and is switched to
deep buffer mode. Updated stream type for tunnel case in
AudioOutput after AudioTrack is created

CRs-Fixed: 774774

Change-Id: I408441c8c0562ef36beddd4f6efb76752d3fb0a0