arc: Add fstatfs64 to existing fstatfs ARM policies

This is a commit to future-proof seccomp failures with syscall=267,
fstatfs64. On 32bit systems, we've seen programs which use not just
fstatfs, but also fstatfs64. Which one is selected is seamlessly
selected via defines via `statvfs`, depending on the board
(notably scarlet, trogdor, and elm differ from other ARM devices).

BUG=b:197006863
TEST=CQ

Change-Id: I1d0a7442f1e332cd363b6acbf4950cebe8a2e1d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/3101706
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: Yusuke Sato <yusukes@chromium.org>
Tested-by: Manoj Gupta <manojgupta@chromium.org>
diff --git a/arc/data-snapshotd/seccomp/arc-data-snapshotd-seccomp-arm.policy b/arc/data-snapshotd/seccomp/arc-data-snapshotd-seccomp-arm.policy
index 5dc59c8..611017f 100644
--- a/arc/data-snapshotd/seccomp/arc-data-snapshotd-seccomp-arm.policy
+++ b/arc/data-snapshotd/seccomp/arc-data-snapshotd-seccomp-arm.policy
@@ -111,5 +111,6 @@
 newfstatat: 1
 pipe: 1
 fstatfs: 1
+fstatfs64: 1
 renameat: 1
 renameat2: 1