Mesa 20.0's RADV Driver Deems Navi/GFX10 Stable, Vulkan 1.2 In Good Shape, ACO Fixes

With Mesa 20.0 scheduled for branching today (though that could be delayed a few days potentially depending upon last minute requests), there's been a flurry of Radeon Vulkan "RADV" driver activity to squeeze into this first Mesa release series of 2020.

Some of the work hitting the Mesa 20.0.0-devel Git tree today includes:

- GFX10/Navi is considered conformant. When starting a Vulkan app/game with GFX10/Navi hardware, the RADV driver will no longer print a warning about not being a conformant Vulkan implementation... It probably was safe enough to remove this warning some time ago, but they just did today in time for the 20.0 branching. Navi RADV support has been overall in good standing for a while.

- RADV's PhysicalDeviceProperties2 now exposes Vulkan 1.2.0. Going back to the Vulkan 1.2 launch day earlier this month were the RADV patches for Vulkan 1.2 while this last minute change is about exposing the conformance version for GetPhysicalDeviceProperties2.

- Exposing VK_AMD_shader_explicit_vertex_parameter, which exposes the SPIR-V AMD_shader_explicit_vertex_parameter support, and this support also in place for ACO.

- More Valve ACO compiler back-end fixes, coming days after the ACO support was settled for the AMD GCN 1.0 "Southern Islands" graphics processors.

While contingent upon the number of Mesa 20.0 release candidates ultimately needed, Mesa 20.0 stable should be out around the end of February.