KVM: x86 emulator: fix repne/repnz decoding

The repnz/repne instructions must set rep_prefix to 1 like rep/repe/repz.

This patch correct the disk probe problem met with OpenBSD.

This issue appears with commit e70669ab
because before it, the decoding was done internally to kvm and after it
is done by x86_emulate.c (which doesn't do it correctly).
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/x86_emulate.c

@@ -596,11 +596,10 @@ x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 		case 0xf0:	/* LOCK */
 			lock_prefix = 1;
 			break;
+		case 0xf2:	/* REPNE/REPNZ */
 		case 0xf3:	/* REP/REPE/REPZ */
 			rep_prefix = 1;
 			break;
-		case 0xf2:	/* REPNE/REPNZ */
-			break;
 		default:
 			goto done_prefixes;
 		}