cmd/compile: gofmt

I don't know how this file wasn't gofmted.

Change-Id: I9b3765ae63970b7bc4dc87107f546e64a78e2830
Reviewed-on: https://go-review.googlesource.com/c/146497Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/compile/internal/gc/obj.go

@@ -81,7 +81,7 @@ func printObjHeader(bout *bio.Writer) {
 	if localpkg.Name == "main" {
 		fmt.Fprintf(bout, "main\n")
 	}
-	fmt.Fprintf(bout, "\n")     // header ends with blank line
+	fmt.Fprintf(bout, "\n") // header ends with blank line
 }
 
 func startArchiveEntry(bout *bio.Writer) int64 {