board: 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/board/gdsys/a38x/Makefile b/board/gdsys/a38x/Makefile
index 4b13859..2713633 100644
--- a/board/gdsys/a38x/Makefile
+++ b/board/gdsys/a38x/Makefile
@@ -6,6 +6,6 @@
 
 obj-$(CONFIG_TARGET_CONTROLCENTERDC) += controlcenterdc.o hre.o keyprogram.o dt_helpers.o
 
-ifeq ($(CONFIG_SPL_BUILD),)
+ifeq ($(CONFIG_XPL_BUILD),)
 obj-$(CONFIG_TARGET_CONTROLCENTERDC) += hydra.o ihs_phys.o
 endif