hal: enable support for GKI

With introduction of GKI from kernel 5.4, audio hal
needs to support both GKI and non-GKI kernel builds.
Add an audio feature flag which enables support for GKI.

CRs-Fixed: 2605183
Change-Id: I2d7c68d0006940f6f6939649dae0816456f6f902
7 files changed