drm/i915/gt: reconcile Excess struct member kernel-doc warnings

Document nested struct members with full names as described in
Documentation/doc-guide/kernel-doc.rst.

intel_gsc.h:34: warning: Excess struct member 'gem_obj' description in 'intel_gsc'

Also add missing field member descriptions.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231228234946.12405-1-rdunlap@infradead.org

drivers/gpu/drm/i915/gt/intel_gsc.h

@@ -21,8 +21,11 @@ struct mei_aux_device;
 /**
  * struct intel_gsc - graphics security controller
  *
- * @gem_obj: scratch memory GSC operations
- * @intf : gsc interface
+ * @intf: gsc interface
+ * @intf.adev: MEI aux. device for this @intf
+ * @intf.gem_obj: scratch memory GSC operations
+ * @intf.irq: IRQ for this device (%-1 for no IRQ)
+ * @intf.id: this interface's id number/index
  */
 struct intel_gsc {
 	struct intel_gsc_intf {