COPYING: Add NVIDIA/Khronos license for glxvnd server module

Fixes: 8753218be ("glx: Import glxvnd server module (v2)")
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

COPYING

@@ -1726,3 +1726,33 @@ AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 SUCH DAMAGE.
+
+
+SPDX-License-Identifier: LicenseRef-MIT-Khronos-credit
+
+Copyright (c) 2016, NVIDIA CORPORATION.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and/or associated documentation files (the
+"Materials"), to deal in the Materials without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Materials, and to
+permit persons to whom the Materials are furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be included
+unaltered in all copies or substantial portions of the Materials.
+Any additions, deletions, or changes to the original source files
+must be clearly indicated in accompanying documentation.
+
+If only executable code is distributed, then the accompanying
+documentation must state that "this software is based in part on the
+work of the Khronos Group."
+
+THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.