hal: Add property to set TrueHD buffer size

Add the property audio.truehd.buffer.size.kb to
allow users to set the TrueHD buffer size to
a value other than the default of 2kb. TrueHD
is supported only for compress pass-through
and can be set as IEC format audio.

Change-Id: I97698eb84c7f6fe94219771650654204c203be55