ServiceManager: Make use of kernel exported structures

This patch switches ServiceManager to use the structures exported in the
kernel headers rather then redefining its own.

struct binder_txn is replaced with struct binder_transaction_data and struct
binder_object with struct flat_binder_object, both defined in the binder driver
header <linux/binder.h>.

Change-Id: I3b3e97918173ea35a289e184774ae06193192da3
Signed-off-by: Serban Constantinescu <serban.constantinescu@arm.com>