Conformant open source support for Mali-G57

The open source Panfrost driver for Mali GPUs now supports the new Valhall architecture with fully-conformant OpenGL ES 3.1 on Mali-G57, a Valhall GPU. The final Mesa patches are landing today, and the required kernel patches are queued for merge upstream.

Mali-G57 features in new MediaTek Chromebooks with the MT8192 and MT8195 system-on-chips. With Mesa 22.2 and an appropriate kernel, accelerated graphics will work out of the box on Linux on these laptops.