Parse cookie pair extended option (previously defined).

Define and parse 64-bit timestamp extended option (and minor cleanup).
However, only 32-bits are used at this time.

Requires:
   TCPCT part 2a: TCP header pointer functions
   TCPCT part 2d: cleanup tcp_parse_options

Signed-off-by: William.Allen.Simpson@gmail.com
---
  include/linux/tcp.h  |   10 +++++++++-
  include/net/tcp.h    |   15 ++++++++-------
  net/ipv4/tcp_input.c |   45 +++++++++++++++++++++++++++++++++++++++++++--
  3 files changed, 60 insertions(+), 10 deletions(-)