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/lg/sniper/sniper.c b/board/lg/sniper/sniper.c
index 9d0959f..d4db32e 100644
--- a/board/lg/sniper/sniper.c
+++ b/board/lg/sniper/sniper.c
@@ -54,7 +54,7 @@
 	MUX_SNIPER();
 }
 
-#ifdef CONFIG_SPL_BUILD
+#ifdef CONFIG_XPL_BUILD
 void get_board_mem_timings(struct board_sdrc_timings *timings)
 {
 	timings->mcfg = HYNIX_V_MCFG_200(256 << 20);