drm/doc: Fixing xml documentation warning

"/**" should be used for kernel-doc documentation only.
It causes a warning with the new "in struct body" format.

Signed-off-by: Danilo Cesar Lemes de Paula <danilo.cesar@collabora.co.uk>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Stephan Mueller <smueller@chronox.de>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kernel@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>
Cc: dri-devel <dri-devel@lists.freedesktop.org>
Cc: Graham Whaley <graham.whaley@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

include/drm/drm_modeset_lock.h

@@ -43,19 +43,19 @@ struct drm_modeset_acquire_ctx {
 
 	struct ww_acquire_ctx ww_ctx;
 
-	/**
+	/*
 	 * Contended lock: if a lock is contended you should only call
 	 * drm_modeset_backoff() which drops locks and slow-locks the
 	 * contended lock.
 	 */
 	struct drm_modeset_lock *contended;
 
-	/**
+	/*
 	 * list of held locks (drm_modeset_lock)
 	 */
 	struct list_head locked;
 
-	/**
+	/*
 	 * Trylock mode, use only for panic handlers!
 	 */
 	bool trylock_only;
@@ -70,12 +70,12 @@ struct drm_modeset_acquire_ctx {
  * Used for locking CRTCs and other modeset resources.
  */
 struct drm_modeset_lock {
-	/**
+	/*
 	 * modeset lock
 	 */
 	struct ww_mutex mutex;
 
-	/**
+	/*
 	 * Resources that are locked as part of an atomic update are added
 	 * to a list (so we know what to unlock at the end).
 	 */