rpc: fix getpeerinfo RPCResult `mapped_as` type
rpc: fix getpeerinfo RPCResult `mapped_as` type

and mention it is only available if the asmap config flag is set.


Former-commit-id: 2cfe18e81851c3d3b4d28dad36dca9aa728718f1
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin2,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin