RadeonSI NIR Benchmarks Show Great Progress With Mesa 20.0

Portal already runs in the hundreds of FPS but did see a couple more frames per second after the NIR switch.

SuperTuxKart was one of the few Linux games seeing noticeable uplift after enabling NIR for this AMD OpenGL Linux driver.

For most games the performance was basically the same between TGSI and NIR, which is important itself for being able to transition to NIR by default without regressing the Radeon Linux gaming performance.