Add security hooks to binder and implement the hooks for SELinux.

Add security hooks to the binder and implement the hooks for SELinux.
The security hooks enable security modules such as SELinux to implement
controls over binder IPC.  The security hooks include support for
controlling what process can become the binder context manager
(binder_set_context_mgr), controlling the ability of a process
to invoke a binder transaction/IPC to another process (binder_transaction),
controlling the ability a process to transfer a binder reference to
another process (binder_transfer_binder), and controlling the ability
of a process to transfer an open file to another process (binder_transfer_file).

This support is used by SE Android, http://selinuxproject.org/page/SEAndroid.

Change-Id: I9a64a87825df2e60b9c51400377af4a9cd1c4049
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
stairway: selinux config
stairway: start in permissive mode for now
stairway: avoid binder crash and remove MTK stuff (thx dr shadow) This aligns binder with kernel-common 342a04795db1aec6d9c5f68fa3880359c6f16bba.
stairway: use lzmo to make recovery fit