kcsan: Move interfaces that affects checks to kcsan-checks.h

This moves functions that affect state changing the behaviour of
kcsan_check_access() to kcsan-checks.h. Since these are likely used with
kcsan_check_access() it makes more sense to have them in kcsan-checks.h,
to avoid including all of 'include/linux/kcsan.h'.

No functional change intended.

Acked-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>