radv/ac: fix multisample subpass image.

We weren't adding the fragment position properly.

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Cc: "17.0" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
(cherry picked from commit 059dd171759bb89d915c049de1ca1c93865c21d3)
1 file changed