rockchip: rk3288: extend jerry backlight vcc_led delay time

some jerry panels need more delay time between the vcc_led and bl_en,
so we extend the delay time from 20ms to 120ms.

BUG=chrome-os-partner:42997
TEST=Boot from jerry, and do not flicker again
BRANCH=none

Change-Id: Ifcf84578038eb5c2e5a0dfae936ee63cef671968
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 0b00b6bd108f0aae461085d00819eca08ec892b3
Original-Change-Id: I74999601b41ccac22493cc9cd0bf52cd4dbb8c26
Original-Signed-off-by: huang lin <hl@rock-chips.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/287373
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/11042
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/mainboard/google/veyron_jerry/mainboard.c

@@ -158,7 +158,7 @@ void mainboard_power_on_backlight(void)
 		break;
 	default:
 		gpio_output(GPIO(2, B, 4), 1);	/* BL_PWR_EN */
-		mdelay(20);
+		mdelay(120);
 		gpio_output(GPIO(7, A, 0), 1);	/* LCD_BL */
 		mdelay(10);
 		gpio_output(GPIO_BACKLIGHT, 1);	/* BL_EN */