Mesa's Radeon R600g Driver Adds NIR Support For Pre-Evergreen GPUs

Merged in early July to Mesa 22.2 was the rewritten R600g NIR back-end for improving older AMD Radeon HD 5000/6000 series graphics cards on Linux with this open-source OpenGL driver. That NIR code was limited to "newer" Radeon GPUs supported by the R600g driver while now it's been extended for supporting pre-Evergreen GPUs too...