Use String8/16 c_str [audio mainline modules] am: 946a39f9 am: 36619085 am: 2f7f7b45

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



Change-Id: I30f51753a90c43173cbf1d2ed956d675b0593cc2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>