Tinygrad Gains A Mesa NIR Backend - Initially Supporting NVK/NAK & LLVMpipe Execution

Merged today to the Tinygrad deep learning framework is a Mesa NIR back-end to allow targeting that common intermediate representation used by these open-source Linux GPU drivers. Initially supported with this Tinygrad NIR back-end is the open-source NVIDIA Vulkan driver "NVK" with its Rust-based NAK compiler as well as the CPU-based LLVMpipe driver...