freedreno/ir3/postsched: try to avoid (sy) syncs

Similar to avoidance of `(ss)` syncs, it turns out to be helpful to
avoid `(sy)` syncs as well.  This helps us turn an tex, (sy)alu, tex,
(sy)alu sequence into tex, tex, (sy)alu, alu, which is a big win in
gfxbench gl_fill2.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4923>
1 file changed