drm/rockchip: vop2: Use regcache_sync() to fix suspend/resume

afa965a4 ("drm/rockchip: vop2: fix suspend/resume") uses
regmap_reinit_cache() to fix the suspend/resume issue with the VOP2
driver. During discussion it came up that we should rather use
regcache_sync() instead. As the original patch is already applied
fix this up in this follow-up patch.

Fixes: afa965a4 ("drm/rockchip: vop2: fix suspend/resume")
Cc: stable@vger.kernel.org
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230417123747.2179695-1-s.hauer@pengutronix.de

drivers/gpu/drm/rockchip/rockchip_drm_vop2.c

@@ -215,8 +215,6 @@ struct vop2 {
 	struct vop2_win win[];
 };
 
-static const struct regmap_config vop2_regmap_config;
-
 static struct vop2_video_port *to_vop2_video_port(struct drm_crtc *crtc)
 {
 	return container_of(crtc, struct vop2_video_port, crtc);
@@ -841,11 +839,7 @@ static void vop2_enable(struct vop2 *vop2)
 		return;
 	}
 
-	ret = regmap_reinit_cache(vop2->map, &vop2_regmap_config);
-	if (ret) {
-		drm_err(vop2->drm, "failed to reinit cache: %d\n", ret);
-		return;
-	}
+	regcache_sync(vop2->map);
 
 	if (vop2->data->soc_id == 3566)
 		vop2_writel(vop2, RK3568_OTP_WIN_EN, 1);
@@ -875,6 +869,8 @@ static void vop2_disable(struct vop2 *vop2)
 
 	pm_runtime_put_sync(vop2->dev);
 
+	regcache_mark_dirty(vop2->map);
+
 	clk_disable_unprepare(vop2->aclk);
 	clk_disable_unprepare(vop2->hclk);
 }