audio: Extend HidlUtils for the default wrapper needs

Add conversions used by the default wrapper.

Promote some conversions to pre-V7 interface to reduce
version-based forking in the default wrapper code.

Bug: 142480271
Test: atest android.hardware.audio.common@7.0-util_tests
Change-Id: I93c482eeaf08442271be2656693be5395ca53762
Merged-In: I93c482eeaf08442271be2656693be5395ca53762