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-omap2/omap3/Makefile b/arch/arm/mach-omap2/omap3/Makefile
index 151bdf6..159633e 100644
--- a/arch/arm/mach-omap2/omap3/Makefile
+++ b/arch/arm/mach-omap2/omap3/Makefile
@@ -15,7 +15,7 @@
 obj-y	+= sys_info.o
 obj-y	+= prcm-regs.o
 obj-y	+= hw_data.o
-ifdef CONFIG_SPL_BUILD
+ifdef CONFIG_XPL_BUILD
 obj-$(CONFIG_SPL_OMAP3_ID_NAND)	+= spl_id_nand.o
 endif