selinux: fix misuse of mutex_is_locked()

mutex_is_locked() tests whether the mutex is locked *by any task*, while
here we want to test if it is held *by the current task*. To avoid
false/missed WARNINGs, use lockdep_assert_is_held() and
lockdep_assert_is_not_held() instead, which do the right thing (though
they are a no-op if CONFIG_LOCKDEP=n).

Cc: stable@vger.kernel.org
Fixes: 2554a48f

 ("selinux: measure state and policy capabilities")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>