wrxi: fix links to the Prelim-notes
On the page: https://ohwr.org/project/wrxi/wikis/Prelim-notes In the
- "White Rabbit Node Reference Design" points to https://www.ohwr.org/project/white-rabbit/wikis
- "Reported FPGA utilization summary" points to https://www.ohwr.org/project/white-rabbit/wikis IMHO they should be changed to something else.