mfd: arizona: Add comment to explain non-devm regulator_get

To avoid someone attempting to change this regulator_get back into a
devm_regulator_get put a comment in explaining that devres can't be used
here as the regulator will be destroyed before devres calls
regulator_put.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/arizona-core.c

@@ -683,6 +683,12 @@ int arizona_dev_init(struct arizona *arizona)
 		goto err_early;
 	}
 
+	/**
+	 * Don't use devres here because the only device we have to get
+	 * against is the MFD device and DCVDD will likely be supplied by
+	 * one of its children. Meaning that the regulator will be
+	 * destroyed by the time devres calls regulator put.
+	 */
 	arizona->dcvdd = regulator_get(arizona->dev, "DCVDD");
 	if (IS_ERR(arizona->dcvdd)) {
 		ret = PTR_ERR(arizona->dcvdd);