dev_ns: adopt the android binder driver

Adds device namespace info to Android binder to isolate binder contexts between
device namespaces.

In binder, the first process to call BINDER_SET_CONTEXT_MGR ioctl becomes the
manager with context 0, and thereafter IPC is realized through binder hanldes
obtained from the manager.

Isolation builds on this concept. We associate a separate binder state with
each device namespace such that each namespace has its own context manager.
Binder users within a namespace interact only with the context manager there.
This suffices because binder does not allow IPC not via the context manager.

  [ minor conflicts in Tegra merge in binder.c - Jeremy ]

Changelog:
[16-Aug-2013] v1 - initial version

Change-Id: Icf2e3bce343a5d20fa210cbd13027cbc546cc1e7
Signed-off-by: Oren Laadan <orenl@cellrox.com>
Signed-off-by: Jeremy C. Andrus <jeremya@cs.columbia.edu>