locking/barriers, kcsan: Add instrumentation for barriers

Adds the required KCSAN instrumentation for barriers if CONFIG_SMP.
KCSAN supports modeling the effects of:

	smp_mb()
	smp_rmb()
	smp_wmb()
	smp_store_release()

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>