RADV Vulkan vs. RadeonSI OpenGL Performance With Linux 4.13 + Mesa 17.3-dev

It's been a few weeks since last delivering any large RADV/RadeonSI open-source AMD Linux graphics benchmark results due to being busy with testing other hardware as well as battling some regressions / stability problems within the AMDGPU DRM code and Mesa Git. But with Linux 4.13 stable and the newest Mesa 17.3-dev code, things are playing well so here are some fresh OpenGL vs. Vulkan benchmarks on three Radeon graphics cards.