freedreno shaderdb

This series gets shader-db working again, using the script that v3d and intel share. I don't like the verbose stats in it, but things like the loop unrolling handling are important. See shader-db!4 (merged) for the patch to make shader-db report.py work across drivers.

Note that this hasn't been tested with actual hardware, only drm-shim, since I haven't set up a HW environment yet.