drm/panel: sitronix-st7703: Don't call disable at shutdown/remove

It's the responsibility of a correctly written DRM modeset driver to
call drm_atomic_helper_shutdown() at shutdown time and that should be
disabling / unpreparing the panel if needed. Panel drivers shouldn't
be calling these functions themselves.

A recent effort was made to fix as many DRM modeset drivers as
possible [1] [2] [3] and most drivers are fixed now.

The compatible strings used by this driver seem to show up across
boards using a variety of DRM drivers. It appears that the relevant
drivers have been converted, but at least one compatible string
doesn't seem to be found in any mainline dts files so we can't be 100%
sure. If it is found that the DRM modeset driver hasn't been fixed
then this patch could be temporarily reverted until it is.

[1] https://lore.kernel.org/r/20230901234015.566018-1-dianders@chromium.org
[2] https://lore.kernel.org/r/20230901234202.566951-1-dianders@chromium.org
[3] https://lore.kernel.org/r/20230921192749.1542462-1-dianders@chromium.org

Cc: Guido Günther <agx@sigxcpu.org>
Cc: Ondřej Jirman <megi@xff.cz>
Cc: Chris Morgan <macromorgan@hotmail.com>
Cc: Frank Oltmanns <frank@oltmanns.dev>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240503143327.RFT.v2.43.I08ba0d4e2d534c06ab0ede9c148bb14cc7c1a9d7@changeid

drivers/gpu/drm/panel/panel-sitronix-st7703.c

@@ -937,27 +937,11 @@ static int st7703_probe(struct mipi_dsi_device *dsi)
 	return 0;
 }
 
-static void st7703_shutdown(struct mipi_dsi_device *dsi)
-{
-	struct st7703 *ctx = mipi_dsi_get_drvdata(dsi);
-	int ret;
-
-	ret = drm_panel_unprepare(&ctx->panel);
-	if (ret < 0)
-		dev_err(&dsi->dev, "Failed to unprepare panel: %d\n", ret);
-
-	ret = drm_panel_disable(&ctx->panel);
-	if (ret < 0)
-		dev_err(&dsi->dev, "Failed to disable panel: %d\n", ret);
-}
-
 static void st7703_remove(struct mipi_dsi_device *dsi)
 {
 	struct st7703 *ctx = mipi_dsi_get_drvdata(dsi);
 	int ret;
 
-	st7703_shutdown(dsi);
-
 	ret = mipi_dsi_detach(dsi);
 	if (ret < 0)
 		dev_err(&dsi->dev, "Failed to detach from DSI host: %d\n", ret);
@@ -981,7 +965,6 @@ MODULE_DEVICE_TABLE(of, st7703_of_match);
 static struct mipi_dsi_driver st7703_driver = {
 	.probe	= st7703_probe,
 	.remove = st7703_remove,
-	.shutdown = st7703_shutdown,
 	.driver = {
 		.name = DRV_NAME,
 		.of_match_table = st7703_of_match,