RMX1921: Add protobuf vendorcompat lib

Our blobs are compiled against libprotobuf-full-cpp.so, but
starting in R, Android is using a versioned naming approach,
e.g. libprotobuf-cpp-full-3.9.1.so.

See https://r.android.com/1109518

The entry in public.libraries.txt is needed to allow the
linker to find and use the lib outside the VNDK.

See https://source.android.com/devices/tech/config/namespaces_libraries



[wight554: added libprotobuf-cpp-lite as well]

Change-Id: I28222c89e1e07017867088492a726ee9d45d8e6f
Signed-off-by: kaderbava <ksbava7325@gmail.com>