docs: arm: marvell: replace stale links with archive links

Marvell has an annoying habit of moving stuff around their web site
every full moon, and often just removing documents altogether.

At this point basically none but four of the links still works and even
those that work today weren't working for a long period of time
previously. That is a shame because (short of the product briefs) the
documents tend to be quite useful.

Let's replace them with known working versions of IA's Wayback Machine
links. That seems to be about the only way of getting a URL that's going
to work the next week.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lore.kernel.org/r/20210215220839.423709-2-lkundrak@v3.skSigned-off-by: Jonathan Corbet <corbet@lwn.net>