Define and use DRC-specific volume curves when applicable

Add support for property defining whether a DRC on the speaker path
 is enabled and will boost soft sounds.
Define new volume curves with more attenuations than existing ones
 to compensate for DRC-induced boost on sonification sounds to
 provide a more "linear" control to the user over the applied volume.

Bug 11600699

Change-Id: If23dd097a8b9b5ebb61e75dd8512ff75e63ba899
Merge remote-tracking branch 'aosp/kitkat-mr1-release' into kk-4.4
Merge commit tag 'android-4.4.1_r1 into kk-4.4
audio: Disable sonification on digital USB outputs

 * We don't want to hear touch sounds on our badass USB DACs. Just
   play the damn music, please :)

Change-Id: I08b1c5d672d853fc7116c03cd77b8828881d3a5b
audio: fix offload enabling test parameter

passing NULL as the default to property_get doesn't return false,
it returns random memory junk that evaluates to true... Explicitly
default the state of this property to "false" as a default

Change-Id: Ib2808bf2540b2b4fdf754d489fb44aa5d9e061a8
Merge remote-tracking branch 'cm/cm-11.0' into kk-4.4