meta,i965: Rip GL_EXT_texture_multisample_blit_scaled support out of meta
i965 is the only driver that ever linked to this code and it's been
doing it in BLORP for a long time now. The only possible case where it
would have fallen back to meta was for depth/stencil but that should
have ended starting with
6cec618e82aa2. Rip out the dead code.
Acked-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4622>