drm/i915: Add some boring kerneldoc

drm/i915: Add some boring kerneldoc

Tooling appears very strict so lets pacify it by adding some comments,
even if fields are completely self-explanatory.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: b11236486749 ("drm/i915: Add GuC submission interface version query")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Jose Souza <jose.souza@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240219132517.1868604-1-tvrtko.ursulin@linux.intel.com