Thanks for testing!
The main problem with the DSI drivers is that the kernel ends up in an endless probe loop if something is wrong (eg a driver missing or not initializing) without telling you what failed - several drivers just silently pass on errors without logging anything so there's no chance of finding out which of the sub-sub-sub components are missing or failing to initialize.
I get the same lockup (endless probe/bind loop) here with the 7inch dtoverlay loaded. I don't have the display, so I'd expect things to fail, but not as badly as they do (unable to complete kernel boot) and tons of meaningless errors on the serial console.
At the moment I'm at a complete loss, I think I have all the required dependencies enabled and no idea what else might be missing.
so long,
Hias