Use LLNDK guard instead of builtin_available

APEXSUPPORT_API was a workaround when we had no support for
__ANDROID_VENDOR_API__. Since we have it now, use it instead of
builtin_available(android APEXSUPPORT_API).

Bug: 302088370
Test: CtsMediaAudioTestCases
Change-Id: I28b0e0ebab5f357a2f5cc29f244ae5494e379fbe
2 files changed