drm/mediatek: dsi: Fix DSI host and panel bridge pre-enable order

Since commit c9b1150 ("drm/atomic-helper: Re-order bridge chain
pre-enable and post-disable"), the bridge pre_enable callbacks are now
called before crtc enable, and the bridge post_disable callbacks after
the crtc disable.
In the mediatek-drm driver, this change leads to transfer errors on
mtk_dsi_host_transfer callback processing during the panel bridge
pre-enable sequence because the DSI host bridge pre_enable and CRTC
enable sequences, that are enabling the required clocks and PHY using
mtk_dsi_poweron function, are called after.

So, in order to fix this call order issue, request the DSI host bridge
be pre-enabled before panel bridge by setting pre_enable_prev_first
flag on DSI device bridge in the mtk_dsi_host_attach function.

Fixes: c9b1150 ("drm/atomic-helper: Re-order bridge chain pre-enable and post-disable")
Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20250701-mediatek-drm-fix-dsi-panel-init-v1-1-7af4adb9fdeb@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

Author: laeyraud

drivers/gpu/drm/mediatek/mtk_dsi.c

@@ -1002,6 +1002,12 @@ static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
 			return PTR_ERR(dsi->next_bridge);
 	}
 
+	/*
+	 * set flag to request the DSI host bridge be pre-enabled before device bridge
+	 * in the chain, so the DSI host is ready when the device bridge is pre-enabled
+	 */
+	dsi->next_bridge->pre_enable_prev_first = true;
+
 	drm_bridge_add(&dsi->bridge);
 
 	ret = component_add(host->dev, &mtk_dsi_component_ops);