zink: add a draw barrier when unbinding a sampler-bound fb surface

this is guaranteed to need some kind of layout change, so ensure the
barrier actually happens

cc: mesa-stable

SoroushIMG <soroush.kashani@imgtec.com>

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18855>
(cherry picked from commit 5bc19dd5f7)

.pick_status.json

@@ -76,7 +76,7 @@
         "description": "zink: add a draw barrier when unbinding a sampler-bound fb surface",
         "nominated": true,
         "nomination_type": 0,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null
     },

src/gallium/drivers/zink/zink_context.c

@@ -2775,8 +2775,10 @@ unbind_fb_surface(struct zink_context *ctx, struct pipe_surface *surf, unsigned
    res->fb_binds--;
    if (!res->fb_binds) {
       check_resource_for_batch_ref(ctx, res);
-      if (res->sampler_bind_count[0])
+      if (res->sampler_bind_count[0]) {
          update_res_sampler_layouts(ctx, res);
+         _mesa_set_add(ctx->need_barriers[0], res);
+      }
    }
 }