The pass is useful for EXT_shader_framebuffer_fetch, not just blend
shaders, so we should do it with the other lowering passes in
midgard_compile_shader_nir.
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5755>
Structure ourselves as a NIR pass replacing loads/stores with
unpacked/packed versions as necessary. Not actually functional yet.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5265>