drm/panel: novatek-nt36672a: 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.

Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Benni Steini <bennisteinir@gmail.com>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Tested-by: Joel Selvaraj <jo@jsfamily.in>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240503143327.RFT.v2.18.I13a06b9e6f5920659b1e5d12543b3cd9066383b8@changeid

drivers/gpu/drm/panel/panel-novatek-nt36672a.c

@@ -72,8 +72,6 @@ struct nt36672a_panel {
 	struct regulator_bulk_data supplies[ARRAY_SIZE(nt36672a_regulator_names)];
 
 	struct gpio_desc *reset_gpio;
-
-	bool prepared;
 };
 
 static inline struct nt36672a_panel *to_nt36672a_panel(struct drm_panel *panel)
@@ -119,9 +117,6 @@ static int nt36672a_panel_unprepare(struct drm_panel *panel)
 	struct nt36672a_panel *pinfo = to_nt36672a_panel(panel);
 	int ret;
 
-	if (!pinfo->prepared)
-		return 0;
-
 	/* send off cmds */
 	ret = nt36672a_send_cmds(panel, pinfo->desc->off_cmds,
 				 pinfo->desc->num_off_cmds);
@@ -147,8 +142,6 @@ static int nt36672a_panel_unprepare(struct drm_panel *panel)
 	if (ret < 0)
 		dev_err(panel->dev, "power_off failed ret = %d\n", ret);
 
-	pinfo->prepared = false;
-
 	return ret;
 }
 
@@ -179,9 +172,6 @@ static int nt36672a_panel_prepare(struct drm_panel *panel)
 	struct nt36672a_panel *pinfo = to_nt36672a_panel(panel);
 	int err;
 
-	if (pinfo->prepared)
-		return 0;
-
 	err = nt36672a_panel_power_on(pinfo);
 	if (err < 0)
 		goto poweroff;
@@ -221,8 +211,6 @@ static int nt36672a_panel_prepare(struct drm_panel *panel)
 
 	msleep(120);
 
-	pinfo->prepared = true;
-
 	return 0;
 
 poweroff: