MINOR: net_helper: extend the ip.fp output with an option presence mask

MINOR: net_helper: extend the ip.fp output with an option presence mask

Emeric suggested that it's sometimes convenient to instantly know if a
client has advertised support for window scaling or timestamps for
example. While the info is present in the TCP options output, it's hard
to extract since it respects the options order.

So here we're extending the 56-bit fingerprint with 8 extra bits that
indicate the presence of options 2..8, and any option above 9 for the
last bit. In practice this is sufficient since higher options are not
commonly used. Also TCP option 5 is normally not sent on the SYN (SACK,
only SACK_perm is sent), and echo options 6 & 7 are no longer used
(replaced with timestamps). These fields might be repurposed in the
future if some more meaningful options are to be mapped (e.g. MPTCP,
TFO cookie, auth).