xpl: Rename spl_phase() to xpl_phase()

Rename this function to indicate that it refers to any xPL phase.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/board_f.c b/common/board_f.c
index 154675d..f1bd70f 100644
--- a/common/board_f.c
+++ b/common/board_f.c
@@ -397,7 +397,7 @@
 
 static int reserve_video_from_videoblob(void)
 {
-	if (IS_ENABLED(CONFIG_SPL_VIDEO_HANDOFF) && spl_phase() > PHASE_SPL) {
+	if (IS_ENABLED(CONFIG_SPL_VIDEO_HANDOFF) && xpl_phase() > PHASE_SPL) {
 		struct video_handoff *ho;
 		int ret = 0;