mesa: skip FLUSH_VERTICES() if no samplers were changed

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/mesa/main/uniform_query.cpp

@@ -1079,7 +1079,12 @@ _mesa_uniform(GLint location, GLsizei count, const GLvoid *values,
       count = MIN2(count, (int) (uni->array_elements - offset));
    }
 
-   _mesa_flush_vertices_for_uniforms(ctx, uni);
+   /* We check samplers for changes and flush if needed in the sampler
+    * handling code further down, so just skip them here.
+    */
+   if (!uni->type->is_sampler()) {
+       _mesa_flush_vertices_for_uniforms(ctx, uni);
+   }
 
    /* Store the data in the "actual type" backing storage for the uniform.
     */