glthread: pack glVertexAttribPointer calls better

These parameters can use 8 bits.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27350>

src/mapi/glapi/gen/marshal_XML.py

@@ -61,6 +61,12 @@ class marshal_function(gl_XML.gl_function):
             if (type, param.name) == ('GLint', 'size'):
                 return 'GLpacked16i'
 
+            # glVertexAttrib*Pointer(index)
+            # glVertexArrayVertexBuffer(bindingindex)
+            if ((type, param.name) == ('GLuint', 'index') or
+                (type, param.name) == ('GLuint', 'bindingindex')):
+                return 'GLenum8' # clamped to 0xff
+
         return type
 
     def get_type_size(self, param):