mesa/main: add support for NV21, YUYV, VYUY and their respective RGB channel formats
This MR also adds the lowering of both formats to either PIPE_FORMAT_G8_B8R8_420, G8R8_B8R8 or B8R8_G8R8, respectively, for drivers that can sample directly from YUV textures, but still need CSC through shaders.
This is part of a panfrost-specific MR, which will enable support for those formats: !21109 (merged)