audio: Implement proper parsing of masks in XsdcConversion

Since the parsed XML uses compliant separator for lists
in attribute values, there is no need to use legacy
'maskFromString' function.

Bug: 305281224
Test: atest VtsHalAudioCoreTargetTest
Change-Id: Ib257fd010b923ac651931e5976f9b1363d693f1b
1 file changed