anv: add missing MEDIA_STATE_FLUSH for internal shaders

Replicating what we do in genX_cmd_compute.c

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 7ca5c84804 ("anv: add support for simple internal compute shaders")
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30539>

src/intel/vulkan/genX_simple_shader.c

@@ -695,6 +695,7 @@ genX(emit_simple_shader_dispatch)(struct anv_simple_shader *state,
          ggw.RightExecutionMask           = dispatch.right_mask;
          ggw.BottomExecutionMask          = 0xffffffff;
       }
+      anv_batch_emit(batch, GENX(MEDIA_STATE_FLUSH), msf);
 #endif
    }
 }