MALI: bifrost: support sharing regulator with other devices

If the regulator is shared between several devices then the lowest
request voltage that meets the system constraints will be used.

Change-Id: Icb6afcb571bddd6709d352dfad8fc2da80567bc0
Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com>

Author: finley1226

drivers/gpu/arm/bifrost/backend/gpu/mali_kbase_devfreq.c

@@ -106,7 +106,7 @@ kbase_devfreq_target(struct device *dev, unsigned long *target_freq, u32 flags)
 #ifdef CONFIG_REGULATOR
 		if (kbdev->current_voltage == voltage)
 			return 0;
-		err = regulator_set_voltage(kbdev->regulator, voltage, voltage);
+		err = regulator_set_voltage(kbdev->regulator, voltage, INT_MAX);
 		if (err) {
 			dev_err(dev, "Failed to set voltage (%d)\n", err);
 			return err;
@@ -120,7 +120,7 @@ kbase_devfreq_target(struct device *dev, unsigned long *target_freq, u32 flags)
 #ifdef CONFIG_REGULATOR
 	if (kbdev->regulator && kbdev->current_voltage != voltage
 			&& kbdev->current_freq < freq) {
-		err = regulator_set_voltage(kbdev->regulator, voltage, voltage);
+		err = regulator_set_voltage(kbdev->regulator, voltage, INT_MAX);
 		if (err) {
 			dev_err(dev, "Failed to increase voltage (%d)\n", err);
 			return err;
@@ -138,7 +138,7 @@ kbase_devfreq_target(struct device *dev, unsigned long *target_freq, u32 flags)
 #ifdef CONFIG_REGULATOR
 	if (kbdev->regulator && kbdev->current_voltage != voltage
 			&& kbdev->current_freq > freq) {
-		err = regulator_set_voltage(kbdev->regulator, voltage, voltage);
+		err = regulator_set_voltage(kbdev->regulator, voltage, INT_MAX);
 		if (err) {
 			dev_err(dev, "Failed to decrease voltage (%d)\n", err);
 			return err;