staging:android: Introduce the use of the managed version of kzalloc

This patch moves shared private data kzalloc to managed devm_kzalloc and
cleans now unneccessary kfree in probe and remove functions.

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>