Bluetooth: Add definitions for link key types

Introduce the link key types defs and use them instead of magic numbers.

Signed-off-by: Waldemar Rymarkiewicz <waldemar.rymarkiewicz@tieto.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 6138e31..e0a3cf1 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -246,6 +246,15 @@
 #define HCI_AT_GENERAL_BONDING		0x04
 #define HCI_AT_GENERAL_BONDING_MITM	0x05
 
+/* Link Key types */
+#define HCI_LK_COMBINATION		0x00
+#define HCI_LK_LOCAL_UNIT		0x01
+#define HCI_LK_REMOTE_UNIT		0x02
+#define HCI_LK_DEBUG_COMBINATION	0x03
+#define HCI_LK_UNAUTH_COMBINATION	0x04
+#define HCI_LK_AUTH_COMBINATION		0x05
+#define HCI_LK_CHANGED_COMBINATION	0x06
+
 /* -----  HCI Commands ---- */
 #define HCI_OP_NOP			0x0000