dt-bindings: net: dp83869: Update licensing info

Add BSD 2 Clause to the licensing.

CC: Rob Herring <robh@kernel.org>
Signed-off-by: NDan Murphy <dmurphy@ti.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/ti,dp83869.yaml

-# SPDX-License-Identifier: GPL-2.0
+# SPDX-License-Identifier: (GPL-2.0+ OR BSD-2-Clause)
 # Copyright (C) 2019 Texas Instruments Incorporated
 %YAML 1.2
 ---