drm/xe: Move defines before relevant fields

Align on same rule in the whole file: defines then doc then relevant
field, with an empty line to separate fields.

v2:
  - Rebase on drm-xe-next
  - Fix ordering of defines and fields in uAPI (Lucas De Marchi)
v3: Remove useless empty lines (Lucas De Marchi)
v4: Move changelog to commit
v5: Rebase

Reported-by: Oded Gabbay <ogabbay@kernel.org>
Link: https://lists.freedesktop.org/archives/intel-xe/2023-May/004704.html


Signed-off-by: Francois Dugast <francois.dugast@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>