audio: fix mmap output

1. add createMmapBuffer() for vendor to override and create mmap fd.
2. add refineMmapPosition() for vendor to override and update
latency in mmap case.
3. fix testcases position check in mmap case.

Bug: 274456992
Bug: 345591089
Test: atest VtsHalAudioCoreTargetTest
Change-Id: Ie63fdd47c0ddc563d84699dfdf6d4e9b72b5af43