cmd/internal/obj: remove pointless validation

s.Func.Text only can be nil at the moment, otherwise there has
some bugs in compiler's Go rumtime.

Change-Id: Ib2ff9bb977352838e67f2b98a69468f6f350c1f3
Reviewed-on: https://go-review.googlesource.com/123535Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/internal/obj/plist.go

@@ -119,9 +119,6 @@ func (ctxt *Link) InitTextSym(s *LSym, flag int) {
 		ctxt.Diag("InitTextSym double init for %s", s.Name)
 	}
 	s.Func = new(FuncInfo)
-	if s.Func.Text != nil {
-		ctxt.Diag("duplicate TEXT for %s", s.Name)
-	}
 	if s.OnList() {
 		ctxt.Diag("symbol %s listed multiple times", s.Name)
 	}