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/cmd/Makefile b/cmd/Makefile
index 91227f1..ed62e1c 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -3,7 +3,7 @@
 # (C) Copyright 2004-2006
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 
-ifndef CONFIG_SPL_BUILD
+ifndef CONFIG_XPL_BUILD
 # core command
 obj-y += boot.o
 obj-$(CONFIG_CMD_BOOTM) += bootm.o
@@ -247,7 +247,7 @@
 obj-$(CONFIG_ARCH_KEYSTONE) += ti/
 obj-$(CONFIG_ARCH_K3) += ti/
 obj-$(CONFIG_ARCH_OMAP2PLUS) += ti/
-endif # !CONFIG_SPL_BUILD
+endif # !CONFIG_XPL_BUILD
 
 obj-$(CONFIG_$(SPL_)CMD_TLV_EEPROM) += tlv_eeprom.o