KVM: x86 emulator: simplify two-byte opcode check

Two-byte opcode always start with 0x0F and the decode flags
of opcode 0xF0 is always 0, so remove dup check.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/emulate.c

@@ -2375,13 +2375,11 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
 
 	/* Opcode byte(s). */
 	opcode = opcode_table[c->b];
-	if (opcode.flags == 0) {
-		/* Two-byte opcode? */
-		if (c->b == 0x0f) {
-			c->twobyte = 1;
-			c->b = insn_fetch(u8, 1, c->eip);
-			opcode = twobyte_table[c->b];
-		}
+	/* Two-byte opcode? */
+	if (c->b == 0x0f) {
+		c->twobyte = 1;
+		c->b = insn_fetch(u8, 1, c->eip);
+		opcode = twobyte_table[c->b];
 	}
 	c->d = opcode.flags;