drm/panel: remove set but not used variable 'config'

drivers/gpu/drm/panel/panel-truly-nt35597.c:493:31: warning: variable ‘config’ set but not used [-Wunused-but-set-variable]
  const struct nt35597_config *config;
                               ^~~~~~
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200417101401.19388-1-yuehaibing@huawei.com

drivers/gpu/drm/panel/panel-truly-nt35597.c

@@ -490,9 +490,7 @@ static int truly_nt35597_panel_add(struct truly_nt35597 *ctx)
 {
 	struct device *dev = ctx->dev;
 	int ret, i;
-	const struct nt35597_config *config;
 
-	config = ctx->config;
 	for (i = 0; i < ARRAY_SIZE(ctx->supplies); i++)
 		ctx->supplies[i].supply = regulator_names[i];