audio: avoid mute delay when no active stream

-Dialpad touch tone delay is observed when connected USB
 headset. This is beacuse of mute delay during  device switch
-In this usecase, mute delay is not required as there is no
 actual device switch
-Fix is to avoid delay in this usecase.

Change-Id: Ib9e7d7f953f740c9f96c43a104edd0b548421e8d
CRs-Fixed: 706678
audio: Avoid mute delay during stopping of tones.

 - Each time tone is played extra delay added due to
   checkDeviceMuteStrategies during stop of tone.
 - Such mute delay is not needed in this scenario when
   there is no actual device switch.
 - Fix is to avoid mute during stop of tone.

Change-Id: I16e11ab846044fc14cb625cee8bf8273e0e4bcc3
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_hardware_qcom_audio-caf into HEAD