regulator: Fix unbalanced disables/enables in regulator_bulk_{enable,disable} error path

Currently it is possible for regulator_bulk_{enable,disable} operations to
generate unbalanced regulator_{disable,enable} calls in its error path.
In case of an error only those regulators of the bulk operation which actually
had been enabled/disabled should get their original state restored.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/core.c

@@ -1977,7 +1977,7 @@ int regulator_bulk_enable(int num_consumers,
 
 err:
 	printk(KERN_ERR "Failed to enable %s: %d\n", consumers[i].supply, ret);
-	for (i = 0; i < num_consumers; i++)
+	for (--i; i >= 0; --i)
 		regulator_disable(consumers[i].consumer);
 
 	return ret;
@@ -2013,7 +2013,7 @@ int regulator_bulk_disable(int num_consumers,
 err:
 	printk(KERN_ERR "Failed to disable %s: %d\n", consumers[i].supply,
 	       ret);
-	for (i = 0; i < num_consumers; i++)
+	for (--i; i >= 0; --i)
 		regulator_enable(consumers[i].consumer);
 
 	return ret;