Convert CONFIG_SPL_BOARD_INIT to Kconfig

This converts the following to Kconfig:
   CONFIG_SPL_BOARD_INIT

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
[trini: Update the Kconfig logic]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/mach-rockchip/Kconfig b/arch/arm/mach-rockchip/Kconfig
index 740dbdf..6be2ab5 100644
--- a/arch/arm/mach-rockchip/Kconfig
+++ b/arch/arm/mach-rockchip/Kconfig
@@ -14,6 +14,7 @@
 config ROCKCHIP_RK3188
 	bool "Support Rockchip RK3188"
 	select CPU_V7
+	select SPL_BOARD_INIT if SPL
 	select SUPPORT_SPL
 	select SUPPORT_TPL
 	select SPL
@@ -30,6 +31,7 @@
 config ROCKCHIP_RK3288
 	bool "Support Rockchip RK3288"
 	select CPU_V7
+	select SPL_BOARD_INIT if SPL
 	select SUPPORT_SPL
 	select SPL
 	help