glapi: Add (empty) api section for ARB_fragment_layer_viewport

This extension is purely GLSL -- there are no new GL API elements.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

src/mapi/glapi/gen/gl_API.xml

@@ -8312,7 +8312,13 @@
 
 <xi:include href="ARB_ES3_compatibility.xml" xmlns:xi="http://www.w3.org/2001/XInclude"/>
 
-<!-- ARB extensions #128...#131 -->
+<!-- ARB extension #128 -->
+
+<category name="GL_ARB_fragment_layer_viewport" number="129">
+    <!-- No new functions, types, enums. -->
+</category>
+
+<!-- ARB extensions #130..#131 -->
 
 <category name="GL_ARB_explicit_uniform_location" number="128">
     <enum name="MAX_UNIFORM_LOCATIONS" count="1" value="0x826E" >