drivers: 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/drivers/Makefile b/drivers/Makefile
index 1acd94f..1b7db81 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -47,7 +47,7 @@
 
 ifndef CONFIG_TPL_BUILD
 ifndef CONFIG_VPL_BUILD
-ifdef CONFIG_SPL_BUILD
+ifdef CONFIG_XPL_BUILD
 
 obj-$(CONFIG_SPL_CPU) += cpu/
 obj-$(CONFIG_SPL_CRYPTO) += crypto/
@@ -80,7 +80,7 @@
 
 endif
 
-ifeq ($(CONFIG_SPL_BUILD)$(CONFIG_TPL_BUILD),)
+ifeq ($(CONFIG_XPL_BUILD)$(CONFIG_TPL_BUILD),)
 
 obj-y += ata/
 obj-$(CONFIG_DM_DEMO) += demo/