locktorture: Add test scenario for mutex_lock

Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

tools/testing/selftests/rcutorture/configs/lock/CFLIST

 LOCK01
+LOCK02

tools/testing/selftests/rcutorture/configs/lock/LOCK02

+CONFIG_SMP=y
+CONFIG_NR_CPUS=4
+CONFIG_HOTPLUG_CPU=y
+CONFIG_PREEMPT_NONE=n
+CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT=y

tools/testing/selftests/rcutorture/configs/lock/LOCK02.boot

+locktorture.torture_type=mutex_lock