rockchip: rk3288: move setup_led() to firefly-rk3288

Only firefly-rk3288 has the dts node "u-boot,boot-led",
while CONFIG_SPL_LED is not enable, move code to firefly-rk3288
now in case someone need this code.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/mach-rockchip/rk3288/Kconfig b/arch/arm/mach-rockchip/rk3288/Kconfig
index de8d9c2..6e3ab1d 100644
--- a/arch/arm/mach-rockchip/rk3288/Kconfig
+++ b/arch/arm/mach-rockchip/rk3288/Kconfig
@@ -66,6 +66,7 @@
 config TARGET_FIREFLY_RK3288
 	bool "Firefly-RK3288"
 	select BOARD_LATE_INIT
+	select SPL_BOARD_INIT if SPL
 	help
 	  Firefly is a RK3288-based development board with 2 USB ports,
 	  HDMI, VGA, micro-SD card, audio, WiFi  and Gigabit Ethernet, It