mfd: 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: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/pcf50633-core.c b/drivers/mfd/pcf50633-core.c
index dc95ddb..710e417 100644
--- a/drivers/mfd/pcf50633-core.c
+++ b/drivers/mfd/pcf50633-core.c
@@ -679,6 +679,7 @@
 	for (i = 0; i < PCF50633_NUM_REGULATORS; i++)
 		platform_device_unregister(pcf->regulator_pdev[i]);
 
+	i2c_set_clientdata(client, NULL);
 	kfree(pcf);
 
 	return 0;