mesa: don't ever bind NullBufferObj for glBindBuffer targets

Since VAOs don't use NullBufferObj for vertex attribs anymore, let's remove
more uses of NullBufferObj.

Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4466>
16 files changed