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/st/common/cmd_stboard.c b/board/st/common/cmd_stboard.c
index 50da063..b9d0abd 100644
--- a/board/st/common/cmd_stboard.c
+++ b/board/st/common/cmd_stboard.c
@@ -29,7 +29,7 @@
  *   Board: MB<Board> Var<VarCPN>.<VarFG> Rev.<Revision>-<BOM>
  */
 
-#ifndef CONFIG_SPL_BUILD
+#ifndef CONFIG_XPL_BUILD
 #include <command.h>
 #include <console.h>
 #include <misc.h>
diff --git a/board/st/stm32f746-disco/stm32f746-disco.c b/board/st/stm32f746-disco/stm32f746-disco.c
index 6d86e4f..8966a09 100644
--- a/board/st/stm32f746-disco/stm32f746-disco.c
+++ b/board/st/stm32f746-disco/stm32f746-disco.c
@@ -27,7 +27,7 @@
 
 int dram_init(void)
 {
-#ifndef CONFIG_SPL_BUILD
+#ifndef CONFIG_XPL_BUILD
 	int rv;
 	struct udevice *dev;
 	rv = uclass_get_device(UCLASS_RAM, 0, &dev);
@@ -45,7 +45,7 @@
 	return fdtdec_setup_memory_banksize();
 }
 
-#ifdef CONFIG_SPL_BUILD
+#ifdef CONFIG_XPL_BUILD
 #ifdef CONFIG_SPL_OS_BOOT
 int spl_start_uboot(void)
 {
diff --git a/board/st/stm32mp1/Makefile b/board/st/stm32mp1/Makefile
index f2d720b..5e39b7b 100644
--- a/board/st/stm32mp1/Makefile
+++ b/board/st/stm32mp1/Makefile
@@ -3,7 +3,7 @@
 # Copyright (C) 2018, STMicroelectronics - All Rights Reserved
 #
 
-ifdef CONFIG_SPL_BUILD
+ifdef CONFIG_XPL_BUILD
 obj-y += spl.o
 else
 obj-y += stm32mp1.o