Input: qt1070 - remove obsolete cleanup for clientdata

A few new i2c-drivers came into the kernel which clear the clientdata
pointer on exit or error. This is not required anymore since the core
will do it for us.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>