It is available on the EM5 mkii. I forget how to activate it (probably similar to other Olympus cameras), but I use it all the time.
Try menu, exposure, AEL metering, and select the spot meter option.I’ve looked through the manual and couldn’t find it. Happy to be proved wrong though.
Then just below, go into the spot meter menu and make sure the three boxes are checked.
Edit: it seems as if this requires firmware 3.0 or later for the EM5 mkii.