drm/xe: Fix missing kernel-doc

Fix warning:

	Warning: drivers/gpu/drm/xe/xe_device_types.h:658 struct member 'wa_active' not described in 'xe_device'

Fixes: 661a695 ("drm/xe: Add infrastructure for Device OOB workarounds")
Cc: Matt Atwood <matthew.s.atwood@intel.com>
Reviewed-by: Jonathan Cavitt <joanthan.cavitt@intel.com>
Link: https://lore.kernel.org/r/20250711214911.2009714-2-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

Author: Lucas De Marchi

drivers/gpu/drm/xe/xe_device_types.h

@@ -363,6 +363,7 @@ struct xe_device {
 		u8 skip_pcode:1;
 	} info;
 
+	/** @wa_active: keep track of active workarounds */
 	struct {
 		/** @wa_active.oob: bitmap with active OOB workarounds */
 		unsigned long *oob;