seccomp: fix fallback definitions of some SECCOMP_* constants

* seccomp.c (SECCOMP_SET_MODE_STRICT, SECCOMP_SET_MODE_FILTER,
SECCOMP_FILTER_FLAG_TSYNC): Remove fallback definitions.
* xlat/seccomp_filter_flags.in: Add default value.
* xlat/seccomp_ops.in: Add default values.
3 files changed