Enable setting security contexts on rootfs inodes.

rootfs (ramfs) can support setting of security contexts
by userspace due to the vfs fallback behavior of calling
the security module to set the in-core inode state
for security.* attributes when the filesystem does not
provide an xattr handler.  No xattr handler required
as the inodes are pinned in memory and have no backing
store.

This is useful in allowing early userspace to label individual
files within a rootfs while still providing a policy-defined
default via genfs.

Change-Id: I95d287398508aacb706544bdbfa58c104a8fe5df
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Android.mk: update for aosp 4.3.2

For AOSP: Rename kernel.mk to Android.mk
and type  "make kernel" in android repo root folder
rcu: add missing trace include file and sync with linux kernel

kernel is broken with CONFIG_RCU_TRACE (since P4 commits)

from linux commits merged the 29 Sep 2011:
 29c00b4a1d9e277786120032aa8364631820d863 (17 Jun 2011)
    rcu: Add event-tracing for RCU callback invocation
 965a002b4f1a458c5dcb334ec29f48a0046faa25 (18 Jun 2011)
    rcu: Make TINY_RCU also use softirq for RCU_BOOST=n
 e99033c5c160f1f247c665923a66acec693a967c (21 Jun 2011)
    rcu: Put names into TINY_RCU structures under RCU_TRACE
 72fe701b70e6ced35d734b676c13efbc8fc769a9 (21 Jun 2011)
    rcu: Add RCU type to callback-invocation tracing
 d4c08f2ac311a360230eef7e5395b0ec8d8f0670 (25 Jun 2011)
    rcu: Add grace-period, quiescent-state, and call_rcu trace events
si4709: fix __devexit remove proc