drm/mediatek: Return from mtk_ovl_layer_config after mtk_ovl_layer_off

If the plane pending state is disabled, call mtk_ovl_layer_off then
return.
This guarantees that that the state is valid for all operations when the
pending state is enabled.
Suggested-by: Sean Paul <seanpaul@chromium.org>
To: CK Hu <ck.hu@mediatek.com>
To: dri-devel@lists.freedesktop.org
Cc: Daniele Castagna <dcastagna@chromium.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mediatek@lists.infradead.org
Signed-off-by: Mark Yacoub <markyacoub@google.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: CK Hu <ck.hu@mediatek.com>

drivers/gpu/drm/mediatek/mtk_disp_ovl.c

@@ -260,8 +260,10 @@ static void mtk_ovl_layer_config(struct mtk_ddp_comp *comp, unsigned int idx,
 	unsigned int src_size = (pending->height << 16) | pending->width;
 	unsigned int con;
 
-	if (!pending->enable)
+	if (!pending->enable) {
 		mtk_ovl_layer_off(comp, idx, cmdq_pkt);
+		return;
+	}
 
 	con = ovl_fmt_convert(ovl, fmt);
 	if (idx != 0)
@@ -288,7 +290,6 @@ static void mtk_ovl_layer_config(struct mtk_ddp_comp *comp, unsigned int idx,
 	mtk_ddp_write_relaxed(cmdq_pkt, addr, comp,
 			      DISP_REG_OVL_ADDR(ovl, idx));
 
-	if (pending->enable)
 	mtk_ovl_layer_on(comp, idx, cmdq_pkt);
 }