Use String8/16 c_str [audio mainline modules] am: 946a39f9

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/24437201



Change-Id: Ib8a8f2ad45e8c283bbaaacf40e815f3850116a96
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>