Add new "Yocto" wiki page.
The way to organize is to properly categorize pages. Then, if you click on Category:Yocto for example, you'd list all pages within the Yocto category. Believe me, I'd love for this to be the case, but I haven't had the time to review all of the pages and categorize them properly. It's on my todo list though.
I'd had an idea a while ago to provide a form on the front page from which a user could select their board and have the wiki return all of the pages relevant to that board. This is in effect bypassing the selection of the Category as I described above. It requires proper and complete categorization of all of the pages though.
You're welcome to add Yocto sections to any hardware pages though. I'm sure the Yocto and the hardware vendors would be appreciative.