Sort includes and split them in blocks:

1) .h corresponding to the .c. Example: xe_bb.c should have a "#include
   "xe_bb.h" first.
2) #include <linux/...>
3) #include <drm/...>
4) local includes
5) i915 includes

This is accomplished by running
`clang-format --style=file -i --sort-includes drivers/gpu/drm/xe/*.[ch]`
and ignoring all the changes after the includes. There are also some
manual tweaks to split the blocks.

v2: Also sort includes in headers
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>