selftests: Add futex functional tests

selftests: Add futex functional tests

The futextest testsuite [1] provides functional, stress, and
performance tests for the various futex op codes. Those tests will be of
more use to futex developers if they are included with the kernel
source.

Copy the core infrastructure and the functional tests into selftests,
but adapt them for inclusion in the kernel:

- Update the Makefile to include the run_tests target, remove reference
  to the performance and stress tests from the contributed sources.
- Replace my dead IBM email address with my current Intel email address.
- Remove the warrantee and write-to paragraphs from the license blurbs.
- Remove the NAME section as the filename is easily determined. ;-)
- Make the whitespace usage consistent in a couple of places.
- Cleanup various CodingStyle violations.

A future effort will explore moving the performance and stress tests
into the kernel.

1. http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git

Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: linux-api@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>