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/x86/cpu/broadwell/pch.c b/arch/x86/cpu/broadwell/pch.c
index 2c8b738..5b61474 100644
--- a/arch/x86/cpu/broadwell/pch.c
+++ b/arch/x86/cpu/broadwell/pch.c
@@ -606,7 +606,7 @@
 			return broadwell_pch_early_init(dev);
 		else
 			return broadwell_pch_init(dev);
-	} else if (IS_ENABLED(CONFIG_SPL) && !IS_ENABLED(CONFIG_SPL_BUILD)) {
+	} else if (IS_ENABLED(CONFIG_SPL) && !IS_ENABLED(CONFIG_XPL_BUILD)) {
 		return broadwell_pch_init(dev);
 	} else {
 		return 0;