OPP: Use opp_table->regulators to verify no regulator case

The value of opp_table->regulator_count is not very consistent right now
and it may end up being 0 while we do have a "opp-microvolt" property in
the OPP table. It was kept that way as we used to check if any
regulators are set with the OPP core for a device or not using value of
regulator_count.

Lets use opp_table->regulators for that purpose as the meaning of
regulator_count is going to change in the later patches.
Reported-by: Quentin Perret <quentin.perret@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/opp/core.c

@@ -196,12 +196,12 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
 	if (IS_ERR(opp_table))
 		return 0;
 
-	count = opp_table->regulator_count;
-
 	/* Regulator may not be required for the device */
-	if (!count)
+	if (!opp_table->regulators)
 		goto put_opp_table;
 
+	count = opp_table->regulator_count;
+
 	uV = kmalloc_array(count, sizeof(*uV), GFP_KERNEL);
 	if (!uV)
 		goto put_opp_table;
@@ -1049,6 +1049,9 @@ static bool _opp_supported_by_regulators(struct dev_pm_opp *opp,
 	struct regulator *reg;
 	int i;
 
+	if (!opp_table->regulators)
+		return true;
+
 	for (i = 0; i < opp_table->regulator_count; i++) {
 		reg = opp_table->regulators[i];
 
@@ -1333,7 +1336,7 @@ static int _allocate_set_opp_data(struct opp_table *opp_table)
 	struct dev_pm_set_opp_data *data;
 	int len, count = opp_table->regulator_count;
 
-	if (WARN_ON(!count))
+	if (WARN_ON(!opp_table->regulators))
 		return -EINVAL;
 
 	/* space for set_opp_data */