board: Use CONFIG_XPL_BUILD instead of CONFIG_SPL_BUILD

Use the new symbol to refer to any 'SPL' build, including TPL and VPL

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/udoo/neo/neo.c b/board/udoo/neo/neo.c
index 4cf214b..bc30bda 100644
--- a/board/udoo/neo/neo.c
+++ b/board/udoo/neo/neo.c
@@ -209,7 +209,7 @@
 	return 0;
 }
 
-#ifdef CONFIG_SPL_BUILD
+#ifdef CONFIG_XPL_BUILD
 
 #include <linux/libfdt.h>
 #include <asm/arch/mx6-ddr.h>