global: Use CONFIG_XPL_BUILD instead of CONFIG_SPL_BUILD

Complete this rename for all directories outside arch/ board/ drivers/
and include/

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/config.mk b/config.mk
index b915c29..e294be2 100644
--- a/config.mk
+++ b/config.mk
@@ -21,7 +21,7 @@
 
 ARCH := $(CONFIG_SYS_ARCH:"%"=%)
 CPU := $(CONFIG_SYS_CPU:"%"=%)
-ifdef CONFIG_SPL_BUILD
+ifdef CONFIG_XPL_BUILD
 ifdef CONFIG_ARCH_TEGRA
 CPU := arm720t
 endif