Enable futex tests to be built and run with the make kselftest and
associated targets.

Most of the tests require escalated privileges. These return ERROR, and
run.sh continues.

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: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NShuah Khan <shuahkh@osg.samsung.com>