Turn on green LED in u-boot

Use the LED as the power on indicator

Change-Id: I90e19eb627e955f2bf2ed4c2acf61258f1b51c1c
diff --git a/board/mediatek/mt8516-coral/mt8516-coral.c b/board/mediatek/mt8516-coral/mt8516-coral.c
index c36765f..fb813fd 100644
--- a/board/mediatek/mt8516-coral/mt8516-coral.c
+++ b/board/mediatek/mt8516-coral/mt8516-coral.c
@@ -7,6 +7,7 @@
 #include <dm.h>
 #include <i2c.h>
 #include <mmc.h>
+#include <asm/gpio.h>
 #include "../../../drivers/crypto/nxp/a71ch.h"
 #include "../../../drivers/watchdog/mtk_wdt.h"
 
@@ -57,6 +58,10 @@
 		}
 	}
 
+	// Set Green LED on
+	gpio_request(19, "led_green");
+	gpio_direction_output(19, 1);
+
 	// Set a default serial number.
 	// If a crypto chip is detected, override it.
 	env_set("serial#", "0123456789ABCDEF");