drm/panel: simple: Remove unneeded gpiod NULL check

The gpiod API checks for NULL descriptors, so there is no need to
duplicate the check in the driver.
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1500249939-8075-1-git-send-email-festevam@gmail.com

drivers/gpu/drm/panel/panel-simple.c

@@ -187,8 +187,7 @@ static int panel_simple_unprepare(struct drm_panel *panel)
 	if (!p->prepared)
 		return 0;
 
-	if (p->enable_gpio)
-		gpiod_set_value_cansleep(p->enable_gpio, 0);
+	gpiod_set_value_cansleep(p->enable_gpio, 0);
 
 	regulator_disable(p->supply);
 
@@ -214,8 +213,7 @@ static int panel_simple_prepare(struct drm_panel *panel)
 		return err;
 	}
 
-	if (p->enable_gpio)
-		gpiod_set_value_cansleep(p->enable_gpio, 1);
+	gpiod_set_value_cansleep(p->enable_gpio, 1);
 
 	if (p->desc->delay.prepare)
 		msleep(p->desc->delay.prepare);