Bluetooth: Fix mgmt status for LL Privacy experimental feature

The return error when trying to change the setting when a controller is
powered up, shall be MGMT_STATUS_REJECTED. However instead now the error
MGMT_STATUS_NOT_POWERED is used which is exactly the opposite.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

net/bluetooth/mgmt.c

@@ -3982,7 +3982,7 @@ static int set_exp_feature(struct sock *sk, struct hci_dev *hdev,
 		if (hdev_is_powered(hdev))
 			return mgmt_cmd_status(sk, hdev->id,
 					       MGMT_OP_SET_EXP_FEATURE,
-					       MGMT_STATUS_NOT_POWERED);
+					       MGMT_STATUS_REJECTED);
 
 		/* Parameters are limited to a single octet */
 		if (data_len != MGMT_SET_EXP_FEATURE_SIZE + 1)