Bluetooth: Remove magic value in disconnect mgmt handler

This patch replaces the magic value of variable 'reason' by the
proper macro.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index b481663..5aa5592 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -1611,7 +1611,7 @@
 	}
 
 	dc.handle = cpu_to_le16(conn->handle);
-	dc.reason = 0x13; /* Remote User Terminated Connection */
+	dc.reason = HCI_ERROR_REMOTE_USER_TERM;
 
 	err = hci_send_cmd(hdev, HCI_OP_DISCONNECT, sizeof(dc), &dc);
 	if (err < 0)