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/arch/x86/cpu/apollolake/pmc.c b/arch/x86/cpu/apollolake/pmc.c
index 32fd034..bfb8a07 100644
--- a/arch/x86/cpu/apollolake/pmc.c
+++ b/arch/x86/cpu/apollolake/pmc.c
@@ -115,7 +115,7 @@
 				 ARRAY_SIZE(base));
 	if (ret)
 		return log_msg_ret("Missing/short early-regs", ret);
-	if (spl_phase() == PHASE_TPL) {
+	if (xpl_phase() == PHASE_TPL) {
 		upriv->pmc_bar0 = (void *)base[0];
 		upriv->pmc_bar2 = (void *)base[2];
 
@@ -186,7 +186,7 @@
 
 static int apl_pmc_probe(struct udevice *dev)
 {
-	if (spl_phase() == PHASE_TPL) {
+	if (xpl_phase() == PHASE_TPL) {
 		return enable_pmcbar(dev);
 	} else {
 		struct acpi_pmc_upriv *upriv = dev_get_uclass_priv(dev);