Revert "power: regulator: Return success on attempt to disable an always-on regulator"

This reverts commit e17e0ceb83538c015a50b965547f2f4d38f81c5d.

It is advised to return an error when trying to disable an always-on
regulator and let the consumer driver handle the error if needed.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
diff --git a/drivers/power/regulator/regulator-uclass.c b/drivers/power/regulator/regulator-uclass.c
index 39e4627..4511625 100644
--- a/drivers/power/regulator/regulator-uclass.c
+++ b/drivers/power/regulator/regulator-uclass.c
@@ -113,7 +113,7 @@
 
 	uc_pdata = dev_get_uclass_platdata(dev);
 	if (!enable && uc_pdata->always_on)
-		return 0;
+		return -EACCES;
 
 	return ops->set_enable(dev, enable);
 }