asahi: Mark scissor dirty if rast->scissor changes

Although there is a scissor enable bit in the hardware rasterizer state, we
cannot rely on it alone as we also "scissor" to the viewport.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11084>

src/gallium/drivers/asahi/agx_state.c

@@ -170,7 +170,18 @@ static void
 agx_bind_rasterizer_state(struct pipe_context *pctx, void *cso)
 {
    struct agx_context *ctx = agx_context(pctx);
-   ctx->rast = cso;
+   struct agx_rasterizer *so = cso;
+
+   /* Check if scissor state has changed, since scissor enable is part of the
+    * rasterizer state but everything else needed for scissors is part of
+    * viewport/scissor states */
+   bool scissor_changed = (cso == NULL) || (ctx->rast == NULL) ||
+      (ctx->rast->base.scissor != so->base.scissor);
+
+   ctx->rast = so;
+
+   if (scissor_changed)
+      ctx->dirty |= AGX_DIRTY_SCISSOR;
 }
 
 static enum agx_wrap