locktorture: Add test scenario for rwsem_lock

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

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

 LOCK01
 LOCK02
+LOCK03

tools/testing/selftests/rcutorture/configs/lock/LOCK03

+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/LOCK03.boot

+locktorture.torture_type=rwsem_lock