drivers: 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/drivers/clk/altera/clk-agilex.c b/drivers/clk/altera/clk-agilex.c
index bdc7be0..e1ddd02 100644
--- a/drivers/clk/altera/clk-agilex.c
+++ b/drivers/clk/altera/clk-agilex.c
@@ -242,7 +242,7 @@
 	if (!cfg)
 		return;
 
-#ifdef CONFIG_SPL_BUILD
+#ifdef CONFIG_XPL_BUILD
 	/* Always force clock manager into boot mode before any configuration */
 	clk_write_ctrl(plat,
 		       CM_REG_READL(plat, CLKMGR_CTRL) | CLKMGR_CTRL_BOOTMODE);