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/mach-sunxi/Makefile b/arch/arm/mach-sunxi/Makefile
index 3f83c02..eb6a491 100644
--- a/arch/arm/mach-sunxi/Makefile
+++ b/arch/arm/mach-sunxi/Makefile
@@ -29,7 +29,7 @@
 obj-y	+= timer.o
 endif
 
-ifdef CONFIG_SPL_BUILD
+ifdef CONFIG_XPL_BUILD
 obj-y				+= clock.o
 obj-$(CONFIG_MACH_SUNIV)	+= dram_suniv.o
 obj-$(CONFIG_DRAM_SUN4I)	+= dram_sun4i.o