Bluetooth: Add 'Already Paired' error for Pair Device command

To make the behavior predictable when attempting to pair with a device
for which we already have a Link Key or Long Term Key, this patch adds a
new 'Already Paired' error which gets sent in such a scenario.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/include/net/bluetooth/mgmt.h b/include/net/bluetooth/mgmt.h
index 0c737e4..5bf6af9 100644
--- a/include/net/bluetooth/mgmt.h
+++ b/include/net/bluetooth/mgmt.h
@@ -43,6 +43,7 @@
 #define MGMT_STATUS_CANCELLED		0x10
 #define MGMT_STATUS_INVALID_INDEX	0x11
 #define MGMT_STATUS_RFKILLED		0x12
+#define MGMT_STATUS_ALREADY_PAIRED	0x13
 
 struct mgmt_hdr {
 	__le16	opcode;