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/common/spl/Kconfig b/common/spl/Kconfig
index 5ed3f19..92b476e 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -16,6 +16,14 @@
 	help
 	  If you want to build SPL as well as the normal image, say Y.
 
+config SPL_BOARD_INIT
+	depends on SPL
+	bool "Call board-specific initialization in SPL"
+	help
+	  If this option is enabled, U-Boot will call the function
+	  spl_board_init() from board_init_r(). This function should be
+	  provided by the board.
+
 config SPL_RAW_IMAGE_SUPPORT
 	bool "Support SPL loading and booting of RAW images"
 	depends on SPL