spl: use different BOARD_INIT MACRO for spl and tpl

SPL and TPL may not always need spl_board_init() at the same time.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/common/spl/spl.c b/common/spl/spl.c
index 76c1963..1566acd 100644
--- a/common/spl/spl.c
+++ b/common/spl/spl.c
@@ -407,7 +407,7 @@
 	timer_init();
 #endif
 
-#ifdef CONFIG_SPL_BOARD_INIT
+#if CONFIG_IS_ENABLED(BOARD_INIT)
 	spl_board_init();
 #endif