KVM: emulator: cleanup decode_register_operand() a bit

Make code shorter.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

arch/x86/kvm/emulate.c

@@ -1045,13 +1045,9 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
 	}
 
 	op->type = OP_REG;
-	if (ctxt->d & ByteOp) {
-		op->addr.reg = decode_register(ctxt, reg, true);
-		op->bytes = 1;
-	} else {
-		op->addr.reg = decode_register(ctxt, reg, false);
-		op->bytes = ctxt->op_bytes;
-	}
+	op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;
+	op->addr.reg = decode_register(ctxt, reg, ctxt->d & ByteOp);
+
 	fetch_register_operand(op);
 	op->orig_val = op->val;
 }