cmd/compile, cmd/link: fix printf verbs

Found by vet.

Change-Id: I9dbc6208ddbb5b407f4ddd20efbc166aac852cf7
Reviewed-on: https://go-review.googlesource.com/29162
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/ssa/decompose.go

@@ -97,7 +97,7 @@ func decomposeBuiltIn(f *Func) {
 		case t.IsFloat():
 			// floats are never decomposed, even ones bigger than IntSize
 		case t.Size() > f.Config.IntSize:
-			f.Fatalf("undecomposed named type %s %s", name, t)
+			f.Fatalf("undecomposed named type %v %v", name, t)
 		default:
 			newNames = append(newNames, name)
 		}

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

@@ -452,7 +452,7 @@ func relocsym(ctxt *Link, s *Symbol) {
 				// We are linking the final executable, so we
 				// can optimize any TLS IE relocation to LE.
 				if Thearch.TLSIEtoLE == nil {
-					log.Fatalf("internal linking of TLS IE not supported on %s", SysArch.Family)
+					log.Fatalf("internal linking of TLS IE not supported on %v", SysArch.Family)
 				}
 				Thearch.TLSIEtoLE(s, int(off), int(r.Siz))
 				o = int64(ctxt.Tlsoffset)