The function was the last missing piece of the `_POSIX_MESSAGE_PASSING`
option group. Due to lack of signal subsystem in the Zephyr RTOS
the `sigev_notify` member of the `sigevent` structure that describes
the notification cannot be set to `SIGEV_SIGNAL` - this notification
type is not implemented, the function will return -1 and set `errno`
to `ENOSYS`.
`mq_notify` documentation:
https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_notify.htmlFixes#66958
Signed-off-by: Adam Wojasinski <awojasinski@baylibre.com>