cmd/link: fix warning for buildmode=plugin on darwin/amd64

Without this CL, the system linker complains about absolute addressing
in type..eqfunc.*.

Updates #18190

Change-Id: I68db37a7f4c96b16a9c13baffc0f043a3048df6d
Reviewed-on: https://go-review.googlesource.com/59373Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/link/internal/ld/lib.go

@@ -1096,7 +1096,8 @@ func (l *Link) hostlink() {
 		argv = append(argv, "-Wl,-headerpad,1144")
 		if l.DynlinkingGo() {
 			argv = append(argv, "-Wl,-flat_namespace")
-		} else if !SysArch.InFamily(sys.ARM64) && Buildmode != BuildmodePIE {
+		}
+		if Buildmode == BuildmodeExe && !SysArch.InFamily(sys.ARM64) {
 			argv = append(argv, "-Wl,-no_pie")
 		}
 	case objabi.Hopenbsd: