Simplpify enum constant declaration
Simplpify enum constant declaration

We know that fields of struct or union can not have the same value
of id, so we can remove the type check in fielddcl.

k0gaMSX/kcc,8l/scc,k0gaMSX/kcc,k0gaMSX/scc,8l/scc,8l/scc,k0gaMSX/scc,k0gaMSX/scc