mosys: Add fchdir and symlinkat to seccomp

Noticed bunch of failures related to fchdir and symlinkat
in coreutils at crash/ (http://shortn/_GYE0BOd61P).
Based on past experience, mosys could
the reason here so add the syscalls to seccomp.

BUG=None
TEST=CQ

Change-Id: I6ec97455ba424240da43472f8ae5b6ca100ad0ea
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/mosys/+/3145720
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Auto-Submit: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
3 files changed