locking/ww_mutex: Add ww_mutex to tools/testing/selftests

Add the minimal test running (modprobe test-ww_mutex) to the kselftests
CI framework.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-9-chris@chris-wilson.co.ukSigned-off-by: NIngo Molnar <mingo@kernel.org>

tools/testing/selftests/locking/ww_mutex.sh

+#!/bin/sh
+# Runs API tests for struct ww_mutex (Wait/Wound mutexes)
+
+if /sbin/modprobe -q test-ww_mutex; then
+       /sbin/modprobe -q -r test-ww_mutex
+       echo "locking/ww_mutex: ok"
+else
+       echo "locking/ww_mutex: [FAIL]"
+       exit 1
+fi