config: Add legacy specific default/common audio policy conf file

Legacy SPs(8953 & 8937) does not support split A2DP.
BT registers with AOSP A2DP HAL rather than with
vendor BT HAL as the common audio policy conf has only
support for split A2dp and a2dp module(for BT input).
Changes is to support vendor BT HAL and remove split A2DP
by localizing audio policy conf files for these targets
rather than using common audio policy conf file. Same
applies for USB HAL as well.
Remove unsupported mixport profiles from policy conf
for these SPs.

Change-Id: Iba83b88480e998fae0c246b5f176ec27d1834578