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/env/Makefile b/env/Makefile
index 673b979..c5145c1 100644
--- a/env/Makefile
+++ b/env/Makefile
@@ -8,7 +8,7 @@
 obj-$(CONFIG_$(SPL_TPL_)ENV_SUPPORT) += attr.o
 obj-$(CONFIG_$(SPL_TPL_)ENV_SUPPORT) += flags.o
 
-ifndef CONFIG_SPL_BUILD
+ifndef CONFIG_XPL_BUILD
 obj-y += callback.o
 obj-$(CONFIG_ENV_IS_IN_EEPROM) += eeprom.o
 obj-$(CONFIG_ENV_IS_IN_EEPROM) += embedded.o