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/logicpd/imx6/imx6logic.c b/board/logicpd/imx6/imx6logic.c
index 589136f..652994d 100644
--- a/board/logicpd/imx6/imx6logic.c
+++ b/board/logicpd/imx6/imx6logic.c
@@ -135,7 +135,7 @@
 	return 0;
 }
 
-#ifdef CONFIG_SPL_BUILD
+#ifdef CONFIG_XPL_BUILD
 #include <asm/arch/mx6-ddr.h>
 #include <asm/arch/mx6q-ddr.h>
 #include <spl.h>