BUG/MINOR: ssl: Use the sequence number with kTLS and TLS 1.2

BUG/MINOR: ssl: Use the sequence number with kTLS and TLS 1.2

When using TLS 1.2 and kTLS, use the sequence number as the explicit
nonce (what the linux kTLS API calls "iv"), as is strongly recommanded,
and done by most TLS implementations, instead of trying to generate a
pseudo random-number.
In practice, it changes nothing, because the kernel would override that
with the sequence number anyway, but there is no need to have confusing
code that uses statistical_prng_range() anyway.

This should be backported to 3.3.