syscalls/mq_notify01: Cleanup.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
mq_notify/mq_notify02.c: add new error tests

Add EINVAL error tests for mq_notify(2).

Signed-off-by: Zeng Linggang <zenglg.jy@cn.fujitsu.com>