scsi: ufs: host: Hold reference returned by of_parse_phandle()

In ufshcd_populate_vreg(), we should hold the reference returned by
of_parse_phandle() and then use it to call of_node_put() for refcount
balance.

Link: https://lore.kernel.org/r/20220719071529.1081166-1-windhl@126.com
Fixes: aa497613 ("ufs: Add regulator enable support")
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NLiang He <windhl@126.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/ufs/host/ufshcd-pltfrm.c

@@ -108,6 +108,17 @@ static int ufshcd_parse_clock_info(struct ufs_hba *hba)
 	return ret;
 }
 
+static bool phandle_exists(const struct device_node *np,
+			   const char *phandle_name, int index)
+{
+	struct device_node *parse_np = of_parse_phandle(np, phandle_name, index);
+
+	if (parse_np)
+		of_node_put(parse_np);
+
+	return parse_np != NULL;
+}
+
 #define MAX_PROP_SIZE 32
 static int ufshcd_populate_vreg(struct device *dev, const char *name,
 				struct ufs_vreg **out_vreg)
@@ -122,7 +133,7 @@ static int ufshcd_populate_vreg(struct device *dev, const char *name,
 	}
 
 	snprintf(prop_name, MAX_PROP_SIZE, "%s-supply", name);
-	if (!of_parse_phandle(np, prop_name, 0)) {
+	if (!phandle_exists(np, prop_name, 0)) {
 		dev_info(dev, "%s: Unable to find %s regulator, assuming enabled\n",
 				__func__, prop_name);
 		goto out;