CVE-2025-68752

In the Linux kernel, the following vulnerability has been resolved:

iavf: Implement settime64 with -EOPNOTSUPP

ptp_clock_settime() assumes every ptp_clock has implemented settime64().
Stub it with -EOPNOTSUPP to prevent a NULL dereference.

The fix is similar to commit 329d050bbe63 ("gve: Implement settime64
with -EOPNOTSUPP").