drm/panel: ltk500hd1829: 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>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240503143327.RFT.v2.16.I4f574b87fe24765ddd4424437159b37a6481aa1a@changeid

drivers/gpu/drm/panel/panel-leadtek-ltk500hd1829.c

@@ -40,7 +40,6 @@ struct ltk500hd1829 {
 	struct regulator *vcc;
 	struct regulator *iovcc;
 	const struct ltk500hd1829_desc *panel_desc;
-	bool prepared;
 };
 
 static const struct ltk500hd1829_cmd ltk101b4029w_init[] = {
@@ -492,9 +491,6 @@ static int ltk500hd1829_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(panel->dev, "failed to set display off: %d\n", ret);
@@ -510,8 +506,6 @@ static int ltk500hd1829_unprepare(struct drm_panel *panel)
 	regulator_disable(ctx->iovcc);
 	regulator_disable(ctx->vcc);
 
-	ctx->prepared = false;
-
 	return 0;
 }
 
@@ -522,9 +516,6 @@ static int ltk500hd1829_prepare(struct drm_panel *panel)
 	unsigned int i;
 	int ret;
 
-	if (ctx->prepared)
-		return 0;
-
 	ret = regulator_enable(ctx->vcc);
 	if (ret < 0) {
 		dev_err(ctx->dev, "Failed to enable vci supply: %d\n", ret);
@@ -568,8 +559,6 @@ static int ltk500hd1829_prepare(struct drm_panel *panel)
 		goto disable_iovcc;
 	}
 
-	ctx->prepared = true;
-
 	return 0;
 
 disable_iovcc: