bytes: lost edit from earlier CL

R=iant
CC=golang-dev
https://golang.org/cl/5450125

src/pkg/bytes/asm_amd64.s

@@ -94,13 +94,13 @@ TEXT ·Equal(SB),7,$0
 	MOVL	len+8(FP), BX
 	MOVL	len1+24(FP), CX
 	MOVL	$0, AX
-	MOVL	$1, DX
 	CMPL	BX, CX
 	JNE	eqret
 	MOVQ	p+0(FP), SI
 	MOVQ	q+16(FP), DI
 	CLD
 	REP; CMPSB
+	MOVL	$1, DX
 	CMOVLEQ	DX, AX
 eqret:
 	MOVB	AX, ret+32(FP)