hazptr: Upgrade kernel-doc headers

Upgrade the kernel-doc headers for hazptr_acquire(), hazptr_release(),
and hazptr_detach_from_task().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Boqun Feng <boqun@kernel.org>