why not use ktime_get_clocktai_ts64

[Jacob Lifshay]

I was reading in noise.c and noticed you use ktime_get_real_ts64 and
do manual adjustments (the current code is broken if/when there's
another leap second) rather than using ktime_get_clocktai_ts64 which
already handles compensation for leap seconds.

https://git.zx2c4.com/wireguard-linux/tree/drivers/net/wireguard/noise.c?id=7fae4596a269d2f9a6a7d1a8695c3a68ab34f7be#n501

Is there a reason for that?

Jacob