regulator: lp8755: Fix lp8755_regulator_init unwind code

It's safe to pass NULL argument to regulator_unregister(), so we can remove
the NULL checking before calling regulator_unregister().
However pass a ERR_PTR to regulator_unregister() is wrong, so we need to
explicitly set "pchip->rdev[buck_num] = NULL" before goto err_buck.

This patch also includes below cleanups:
Show correct regulator id in dev_err.
Remove __devexit_p.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/lp8755.c

@@ -358,7 +358,9 @@ static int lp8755_regulator_init(struct lp8755_chip *pchip)
 		    regulator_register(&lp8755_regulators[buck_num], &rconfig);
 		if (IS_ERR(pchip->rdev[buck_num])) {
 			ret = PTR_ERR(pchip->rdev[buck_num]);
-			dev_err(pchip->dev, "regulator init failed: buck 0\n");
+			pchip->rdev[buck_num] = NULL;
+			dev_err(pchip->dev, "regulator init failed: buck %d\n",
+				buck_num);
 			goto err_buck;
 		}
 	}
@@ -367,8 +369,7 @@ static int lp8755_regulator_init(struct lp8755_chip *pchip)
 
 err_buck:
 	for (icnt = 0; icnt < LP8755_BUCK_MAX; icnt++)
-		if (pchip->rdev[icnt] != NULL)
-			regulator_unregister(pchip->rdev[icnt]);
+		regulator_unregister(pchip->rdev[icnt]);
 	return ret;
 }
 
@@ -557,7 +558,7 @@ static struct i2c_driver lp8755_i2c_driver = {
 		   .name = LP8755_NAME,
 		   },
 	.probe = lp8755_probe,
-	.remove = __devexit_p(lp8755_remove),
+	.remove = lp8755_remove,
 	.id_table = lp8755_id,
 };