Bluetooth: Add support for vendor specific diagnostic channel

Introduce hci_recv_diag function for HCI drivers to allow sending vendor
specific diagnostic messages into the Bluetooth core stack. The messages
are not processed, but they are forwarded to the monitor channel and can
be retrieved by user space diagnostic tools.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index e7f938c..cf75c43 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -262,6 +262,7 @@
 #define HCI_ACLDATA_PKT		0x02
 #define HCI_SCODATA_PKT		0x03
 #define HCI_EVENT_PKT		0x04
+#define HCI_DIAG_PKT		0xf0
 #define HCI_VENDOR_PKT		0xff
 
 /* HCI packet types */