i915g: Apply clang-format, improve shader debug
Add the format file copied from freedreno, and run clang-format --style=file -i src/gallium/drivers/i915/*.[ch] (with clang-format 11).
Add the format file copied from freedreno, and run clang-format --style=file -i src/gallium/drivers/i915/*.[ch] (with clang-format 11).