drm/panel: ltk050h3146w: Stop tracking prepared

As talked about in commit d2aacaf0 ("drm/panel: Check for already
prepared/enabled in drm_panel"), we want to remove needless code from
panel drivers that was storing and double-checking the
prepared/enabled state. Even if someone was relying on the
double-check before, that double-check is now in the core and not
needed in individual drivers.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240503143327.RFT.v2.14.I264417152e65b4a2e374666010666fa1c2d973fc@changeid

drivers/gpu/drm/panel/panel-leadtek-ltk050h3146w.c

@@ -36,7 +36,6 @@ struct ltk050h3146w {
 	struct regulator *vci;
 	struct regulator *iovcc;
 	const struct ltk050h3146w_desc *panel_desc;
-	bool prepared;
 };
 
 static const struct ltk050h3146w_cmd page1_cmds[] = {
@@ -521,9 +520,6 @@ static int ltk050h3146w_unprepare(struct drm_panel *panel)
 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
 	int ret;
 
-	if (!ctx->prepared)
-		return 0;
-
 	ret = mipi_dsi_dcs_set_display_off(dsi);
 	if (ret < 0) {
 		dev_err(ctx->dev, "failed to set display off: %d\n", ret);
@@ -539,8 +535,6 @@ static int ltk050h3146w_unprepare(struct drm_panel *panel)
 	regulator_disable(ctx->iovcc);
 	regulator_disable(ctx->vci);
 
-	ctx->prepared = false;
-
 	return 0;
 }
 
@@ -550,9 +544,6 @@ static int ltk050h3146w_prepare(struct drm_panel *panel)
 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
 	int ret;
 
-	if (ctx->prepared)
-		return 0;
-
 	dev_dbg(ctx->dev, "Resetting the panel\n");
 	ret = regulator_enable(ctx->vci);
 	if (ret < 0) {
@@ -593,8 +584,6 @@ static int ltk050h3146w_prepare(struct drm_panel *panel)
 
 	msleep(50);
 
-	ctx->prepared = true;
-
 	return 0;
 
 disable_iovcc: