Bluetooth: Add support for handling P-256 derived link keys

Before being able to enable Secure Connections support, the core needs
to know on how to handle P-256 derived link keys. The difference between
authenticated and unauthenticated P-256 derived link keys is the same as
its P-192 counter parts.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index defa125..b3c5396 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -2633,7 +2633,8 @@
 
 	conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, &ev->bdaddr);
 	if (conn) {
-		if (key->type == HCI_LK_UNAUTH_COMBINATION_P192 &&
+		if ((key->type == HCI_LK_UNAUTH_COMBINATION_P192 ||
+		     key->type == HCI_LK_UNAUTH_COMBINATION_P256) &&
 		    conn->auth_type != 0xff && (conn->auth_type & 0x01)) {
 			BT_DBG("%s ignoring unauthenticated key", hdev->name);
 			goto not_found;