5D3: removed EVF_STATEOBJ const and defined EVF_STATE, ported from 6D patch

Created originally on Bitbucket by rufustfirefly (Jeff Buchbinder)

Was already merged in Bitbucket before import, marked as merged by the import user

5D3 support for the same 6D patch that went in earlier today, since it was the only platform that seemed to be left out. :(