Add Pinebook Pro patch for faulty display PSR

On some PBPs from the most recent batch, the PSR feature of the display seems to be broken and results in frequent frame skips and kernel errors. For more information on the issue see: https://forum.pine64.org/showthread.php?tid=10326.

I've written a patch that allows users to disable PSR at the kernel commandline which resolves the issue. I've submitted it upstream here: https://lists.freedesktop.org/archives/dri-devel/2020-June/270505.html. Until it lands upstream though, it would be nice to include here so PBP users on Manjaro can easily apply the fix.