arch: 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/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 67275fb..e343e81 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -21,7 +21,7 @@
 obj-y   += setjmp.o
 endif
 
-ifndef CONFIG_SPL_BUILD
+ifndef CONFIG_XPL_BUILD
 ifdef CONFIG_ARM64
 obj-y	+= relocate_64.o
 else