mfd: rn5t618: Use devm_mfd_add_devices() for mfd_device registration

Use devm_mfd_add_devices() for MFD devices registration and remove
the call of mfd_remove_devices() from .remove callback to remove
MFD child-devices. This is done by managed device framework.

CC: Beniamino Galvani <[e-mail]>
Signed-off-by: Laxman Dewangan <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/rn5t618.c

···
 		return ret;
 	}
 
-	ret = mfd_add_devices(&i2c->dev, -1, rn5t618_cells,
-			      ARRAY_SIZE(rn5t618_cells), NULL, 0, NULL);
+	ret = devm_mfd_add_devices(&i2c->dev, -1, rn5t618_cells,
+				   ARRAY_SIZE(rn5t618_cells), NULL, 0, NULL);
 	if (ret) {
 		dev_err(&i2c->dev, "failed to add sub-devices: %d\n", ret);
 		return ret;
···
 		pm_power_off = NULL;
 	}
 
-	mfd_remove_devices(&i2c->dev);
 	return 0;
 }