Add property data to gensrcs for additional inputs

This enables sandboxing for inputs that are necessary but do not need to
have a source file generated.

Test: GENRULE_SANDBOXING=true m framework-javastream-protos \
      framework-cppstream-protos
Change-Id: Id5ca1dab5799c25fa96b564a7d2008c2e7b5382b