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-keystone/Kconfig b/arch/arm/mach-keystone/Kconfig
index 3ea8dc3..cababdb 100644
--- a/arch/arm/mach-keystone/Kconfig
+++ b/arch/arm/mach-keystone/Kconfig
@@ -6,19 +6,23 @@
 
 config TARGET_K2HK_EVM
 	bool "TI Keystone 2 Kepler/Hawking EVM"
+	select SPL_BOARD_INIT if SPL
 	imply DM_I2C
 
 config TARGET_K2E_EVM
 	bool "TI Keystone 2 Edison EVM"
+	select SPL_BOARD_INIT if SPL
 	imply DM_I2C
 
 config TARGET_K2L_EVM
 	bool "TI Keystone 2 Lamar EVM"
+	select SPL_BOARD_INIT if SPL
 	imply DM_I2C
 
 config TARGET_K2G_EVM
 	bool "TI Keystone 2 Galileo EVM"
         select BOARD_LATE_INIT
+	select SPL_BOARD_INIT if SPL
         select TI_I2C_BOARD_DETECT
 	imply DM_I2C