OrderedTypeEx: remove duplicated cmp definition
OrderedTypeEx: remove duplicated cmp definition

SkySkimmer/coq,coq/coq,Zimmi48/coq,coq/coq,Zimmi48/coq,ejgallego/coq,Zimmi48/coq,SkySkimmer/coq,SkySkimmer/coq,ejgallego/coq,ejgallego/coq,SkySkimmer/coq,Zimmi48/coq,coq/coq,ejgallego/coq,coq/coq