ANDROID: Move -fvisibility-inlines-hidden to CXXFLAGS only

Seeing this error in Android when running `cargo_embargo`:

error: command-line option ‘-fvisibility-inlines-hidden’ is valid
       for C++/ObjC++ but not for C [-Werror]

Test: cargo_embargo generate
Bug: none
Change-Id: Iddfaac9a2e4cce22401b65515dea3ed581e57400
1 file changed