TCP option parsing example uses wrong formats for TCP options

[jafingerhut]

I do not recall what reference I might have been using (if any) for the format of TCP options when I wrote the P4 code in https://github.com/jafingerhut/p4-guide/tree/master/tcp-options-parser, but on 2021-Dec-22 Rob Starr on the p4-lang Slack channel pointed out that several of the options formats do not match their definitions from the relevant RFCs, such as:

• https://datatracker.ietf.org/doc/html/rfc793
• Window Scale option - https://datatracker.ietf.org/doc/html/rfc7323

I am open to someone else submitting fixes for these example programs if they are interested. Happy to keep your name as the author and include your file in this repo, or to link to your published copy from my repo if you prefer.

Note that these TCP options parsing examples were created more as a proof of concept that it is possible within the features of the P4_16 language to parse TCP options. That does not mean that this is a practical thing to do, necessarily, nor that this P4 code will compile on your favorite high speed P4-programmable target device, because some of them probably cannot compile this code (even if it were corrected).