mesa: Remove unnecessary locking from container objects.

mesa: Remove unnecessary locking from container objects.

From Chapter 5 'Shared Objects and Multiple Contexts' of
the OpenGL 4.5 spec:

   "Objects which contain references to other objects include
   framebuffer, program pipeline, query, transform feedback,
   and vertex array objects.   Such objects are called container
   objects and are not shared"

For we leave locking in place for framebuffer objects because
the EXT fbo extension allowed sharing.

V2: (Timothy Arceri)
 - rebased and dropped changes to framebuffer objects

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>