radv: add initial SQ Thread Trace support for GFX9

radv: add initial SQ Thread Trace support for GFX9

SQTT is a hardware block that collects thread trace data (like
wave occupancy, timings, etc) for every draw/dispatch calls.

It's only supported on GFX9 at the moment but I will add other
generations support soon.

This is the first step towards profiling with RADV!

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3900>