libsysdecode: fix decoding of TCP_NOPUSH and TCP_MD5SIG

TCP_FASTOPEN_MIN_COOKIE_LEN was incorrectly registered as a name of
a IPPROTO_TCP level socket option, which overwrote TCP_NOPUSH.
TCP_FASTOPEN_PSK_LEN was incorrectly registered as a name of an
IPPROTO_TCP level socket option, which overwrote TCP_MD5SIG.

MFC after: 3 days
Sponsored by: Netflix, Inc.