Convert CONFIG_SPL_INIT_MINIMAL et al to Kconfig

This converts the following to Kconfig:
   CONFIG_SPL_INIT_MINIMAL
   CONFIG_SPL_FLUSH_IMAGE
   CONFIG_SPL_SKIP_RELOCATE

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/powerpc/cpu/mpc83xx/Makefile b/arch/powerpc/cpu/mpc83xx/Makefile
index 7c4ef76..1255f53 100644
--- a/arch/powerpc/cpu/mpc83xx/Makefile
+++ b/arch/powerpc/cpu/mpc83xx/Makefile
@@ -8,10 +8,12 @@
 MINIMAL=
 
 ifdef CONFIG_SPL_BUILD
+ifndef CONFIG_TPL_BUILD
 ifdef CONFIG_SPL_INIT_MINIMAL
 MINIMAL=y
 endif
 endif
+endif
 
 extra-y	= start.o
 
diff --git a/arch/powerpc/cpu/mpc83xx/start.S b/arch/powerpc/cpu/mpc83xx/start.S
index 0944d19..7a01b16 100644
--- a/arch/powerpc/cpu/mpc83xx/start.S
+++ b/arch/powerpc/cpu/mpc83xx/start.S
@@ -39,7 +39,7 @@
 #endif
 
 #if defined(CONFIG_NAND_SPL) || \
-	(defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_INIT_MINIMAL))
+	(defined(CONFIG_SPL_BUILD) && CONFIG_IS_ENABLED(INIT_MINIMAL))
 #define MINIMAL_SPL
 #endif