mesa: split _NEW_TEXTURE into _NEW_TEXTURE_OBJECT & _NEW_TEXTURE_STATE

mesa: split _NEW_TEXTURE into _NEW_TEXTURE_OBJECT & _NEW_TEXTURE_STATE

No performance testing has been done, because it makes sense to make this
change regardless of that. Also, _NEW_TEXTURE is still used in many places,
but the obvious occurences are replaced here.

It's now possible to split _NEW_TEXTURE_OBJECT further.

Reviewed-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>