Staging: iio: light: fix dangling pointers

Fix I2C-drivers which missed setting clientdata to NULL before freeing the
structure it points to. Also fix drivers which do this _after_ the structure
was freed already.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/light/tsl2563.c

@@ -682,6 +682,7 @@ static int __devinit tsl2563_probe(struct i2c_client *client,
 fail2:
 	iio_device_unregister(chip->indio_dev);
 fail1:
+	i2c_set_clientdata(client, NULL);
 	kfree(chip);
 	return err;
 }
@@ -692,6 +693,7 @@ static int tsl2563_remove(struct i2c_client *client)
 
 	iio_device_unregister(chip->indio_dev);
 
+	i2c_set_clientdata(client, NULL);
 	kfree(chip);
 	return 0;
 }