mesa: Unhook NV_fragment_program API from the dispatch table.

mesa: Unhook NV_fragment_program API from the dispatch table.

The NamedParameter functions were introduced in NV_fragment_program, and
are not shared with any other extensions.

Although this patch appears to remove the LocalParameter functions, it
does not: the ARB_fragment_program section also set them up.  Now we
simply initialize them a single time.

Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Eric Anholt <eric@anholt.net>