* AAC-Decoder

   - Only set the program reference level if it has changed compared to the
     previous value. This allows setting it on a frame-by-frame basis without
     limitations.
     Modified file(s):
        libAACdec/src/aacdec_drc.cpp
        libAACdec/src/aacdec_drc.h

   - Add expiry counter for the program reference level.
     Modified file(s):
        libAACdec/src/aacdec_drc.cpp
        libAACdec/src/aacdec_drc_types.h

   - Disable scaling of light compression gain values when heavy compression
     mode is enabled to have the full light compression as fallback if no heavy
     values are available.
     Modified file(s):
        libAACdec/src/aacdec_drc.cpp
        libAACdec/src/aacdecoder_lib.cpp
        libAACdec/src/aacdec_drc_types.h

   - Change initialization and channel disabling to improve start-up behavior in
     SBR decoder.
     Modified file(s):
        libSBRdec/src/sbrdecoder.cpp
        libSBRdec/src/sbrdec_drc.cpp

Bug 9428126

Change-Id: Ie1d3949c53910506da2547d32fe3bf6ee7606eb4