ppc64/ppc64spec: fix tool name in log prefix and usage

Change-Id: Ic2a89ffb46b3e3d92d9470bbdc64ad9da4578e67
Reviewed-on: https://go-review.googlesource.com/112295
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/ppc64/ppc64spec/spec.go b/ppc64/ppc64spec/spec.go
index 0e60037..f8abf46 100644
--- a/ppc64/ppc64spec/spec.go
+++ b/ppc64/ppc64spec/spec.go
@@ -52,10 +52,10 @@
 
 func main() {
 	log.SetFlags(0)
-	log.SetPrefix("armspec: ")
+	log.SetPrefix("ppc64spec: ")
 
 	if len(os.Args) != 2 {
-		fmt.Fprintf(os.Stderr, "usage: armspec file.pdf\n")
+		fmt.Fprintf(os.Stderr, "usage: ppc64spec file.pdf\n")
 		os.Exit(2)
 	}