radv: Add clang-format for AMD code.

clang-format radv to do away with all the mixed tabs/spaces.

I also looked into CI, but

1. Seems there is a meson clang-format-check in git but not released yet (aka this could be way easier to do in the future)
2. Not sure yet how to deal with different clang-format versions potentially giving different output.

so I decided to hold off with that for now.

You can format your patches with git clang-format.

You can regenerate the effects of this series with

find ./src/amd/vulkan -regex '.*/.*\.\(c\|h\|cpp\)' | xargs -P8 -n1 clang-format --style=file -i