Make OBI specs easier to find
I keep getting two questions about the CV32E40P: 1, What are the memory bus interfaces? 2. Where is the location of the OBI spec.?
Both are clearly answered in the User Manual, but it seems the information is not as easy to find as it might be. This PR puts the OBI reference in the Introduction section, which should make it easy to find. In keeping with the "do not repeat yourself" principle of documentation, the links to the spec from the other chapters that reference it have been removed.
By definition this PR will pass an RTL LE check.
Signed-off-by: Mike Thompson mike@openhwgroup.org