更新500ms闪烁一次

u-boot/arch/arm/mach-arkmicro/armv7/ark1668e_display_cfg.c

@@ -78,7 +78,7 @@ static struct udevice *g_dp;
 
 static void update_led_blinking(int start)
 {
-	#define BACKLIGHT_PWM_PERIOD		1000000000
+	#define BACKLIGHT_PWM_PERIOD		500000000
 	u32 pwm_id = 1;
 
 	/* pad config */