License headers: add SPDX headers

source/blender/draw/engines/eevee_next/shaders/eevee_lookdev_display_frag.glsl

@@ -1,3 +1,7 @@
+/* SPDX-FileCopyrightText: 2023 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
 void main()
 {
   vec2 texture_size = vec2(textureSize(metallic_tx, 0));
@@ -20,4 +24,4 @@ void main()
 
   /* Ensure balls are on top of overlays. */
   gl_FragDepth = 0.0;
-}
+}

source/blender/draw/engines/eevee_next/shaders/eevee_lookdev_display_vert.glsl

@@ -1,3 +1,7 @@
+/* SPDX-FileCopyrightText: 2023 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
 void main()
 {
   uint vert_index = gl_VertexID < 3 ? gl_VertexID : gl_VertexID - 2;
@@ -18,4 +22,4 @@ void main()
                      0.0);
   vec2 co = uv * sphere_size + offset;
   gl_Position = vec4(co, 0.0, 1.0);
-}
+}