newt: Always generate link tables header

Now link tables header will always be generated.
Script that generates default linker scripts requires
this file to exist, so we generate it even when
it is going to be empty.

newt/builder/extcmd.go

@@ -197,14 +197,6 @@ func getLinkTableEntry(name string) string {
 func (t *TargetBuilder) generateLinkTables() {
 	var s []string
 
-	for _, pkg := range t.res.LpkgRpkgMap {
-		s = append(s, pkg.Lpkg.LinkTables()...)
-	}
-
-	if len(s) == 0 {
-		return
-	}
-
 	dir := GeneratedBaseDir(t.target.FullName()) + "/link/include"
 	err := os.MkdirAll(dir, os.ModePerm)
 	if err != nil {
@@ -218,6 +210,14 @@ func (t *TargetBuilder) generateLinkTables() {
 		return
 	}
 
+	for _, pkg := range t.res.LpkgRpkgMap {
+		s = append(s, pkg.Lpkg.LinkTables()...)
+	}
+
+	if len(s) == 0 {
+		return
+	}
+
 	for _, linkTable := range s {
 		linkHeader.WriteString(getLinkTableEntry(linkTable))
 	}