Add LICENSE to third_party/khronos

Pulls license information from subfiles into a single LICENSE file
so that Chromium's tools/licenses.py can read it.

Change-Id: I3fbbca3922193eb5fec361fef833ffc3cfdc9e45
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/100500
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Auto-Submit: Austin Eng <enga@chromium.org>
diff --git a/third_party/khronos/LICENSE b/third_party/khronos/LICENSE
new file mode 100644
index 0000000..f3edea4
--- /dev/null
+++ b/third_party/khronos/LICENSE
@@ -0,0 +1,36 @@
+Copyright 2013-2020 The Khronos Group Inc.
+SPDX-License-Identifier: Apache-2.0
+
+This header is generated from the Khronos EGL XML API Registry.
+The current version of the Registry, generator scripts
+used to make the header, and the header can be found at
+  http://www.khronos.org/registry/egl
+
+Khronos $Git commit SHA1: 6fb1daea15 $ on $Git commit date: 2022-05-25 09:41:13 -0600 $
+
+
+Copyright 2007-2020 The Khronos Group Inc.
+SPDX-License-Identifier: Apache-2.0
+
+Platform-specific types and definitions for egl.h
+
+Adopters may modify khrplatform.h and this file to suit their platform.
+You are encouraged to submit all modifications to the Khronos group so that
+they can be included in future versions of this file.  Please submit changes
+by filing an issue or pull request on the public Khronos EGL Registry, at
+https://www.github.com/KhronosGroup/EGL-Registry/
+
+
+Copyright (c) 2013-2018 The Khronos Group Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.