docs: update ARB_vertex_attrib_64bit status

I started this as well on top of my fp64 stuff.

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/docs/GL3.txt b/docs/GL3.txt
index b9167fa3..9eba525 100644
--- a/docs/GL3.txt
+++ b/docs/GL3.txt
@@ -125,7 +125,7 @@
   GL_ARB_get_program_binary                            DONE (0 binary formats)
   GL_ARB_separate_shader_objects                       DONE (all drivers)
   GL_ARB_shader_precision                              started (Micah)
-  GL_ARB_vertex_attrib_64bit                           not started
+  GL_ARB_vertex_attrib_64bit                           started (Dave)
   GL_ARB_viewport_array                                DONE (i965, nv50, nvc0, r600)