Bluetooth: Print error message for HCI_Hardware_Error event

When the HCI_Hardware_Error event is send by the controller or
injected by the driver, then at least print an error message.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

include/net/bluetooth/hci.h

@@ -1463,6 +1463,11 @@ struct hci_ev_cmd_status {
 	__le16   opcode;
 } __packed;
 
+#define HCI_EV_HARDWARE_ERROR		0x10
+struct hci_ev_hardware_error {
+	__u8     code;
+} __packed;
+
 #define HCI_EV_ROLE_CHANGE		0x12
 struct hci_ev_role_change {
 	__u8     status;