pan/bi: Don't set the back-to-back bit yet

This is bad for performance but we can't assume it's true without some
analysis, which we presently don't do. Leave it for future work and
don't break the present.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4396>

src/panfrost/bifrost/bi_schedule.c

@@ -139,7 +139,7 @@ bi_schedule(bi_context *ctx)
 
                         ids = ids & 1;
                         last_id = u->scoreboard_id;
-                        u->back_to_back = true;
+                        u->back_to_back = false;
 
                         u->constant_count = 1;
                         u->constants[0] = ins->constant.u64;