xlat: update SECCOMP_* constants

xlat: update SECCOMP_* constants

* xlat/seccomp_ops.in (SECCOMP_GET_NOTIF_SIZES): New constant introduced
by Linux kernel commit v5.0-rc1~66^2~1^2~1.
* xlat/seccomp_ret_action.in (SECCOMP_RET_USER_NOTIF): Likewise.
* xlat/seccomp_filter_flags.in (SECCOMP_FILTER_FLAG_NEW_LISTENER):
Likewise.
* NEWS: Mention this.
* tests/seccomp-filter.c (main): Update expected output.
* tests/seccomp-filter-v.c (main): Likewise.
* tests/seccomp_get_action_avail.c (main): Check SECCOMP_RET_USER_NOTIF.