We don't really need the varying remapping, and it seems to somehow
happen twice when shader-cache comes into the picture. But we can
just choose not to have this problem.
Now that everything is using the ir3_point_sprite() helper, we can
flip this pipe cap without it being a massive flag-day.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5595>