xen/xenbus: document will_handle argument for xenbus_watch_path()

Commit 2e85d32b ("xen/xenbus: Add 'will_handle' callback support in
xenbus_watch_path()") added will_handle argument to xenbus_watch_path()
and its wrapper, xenbus_watch_pathfmt(), but didn't document it on the
kerneldoc comments of the function.  This is causing warnings that
reported by kernel test robot.  Add the documentation to fix it.

Fixes: 2e85d32b ("xen/xenbus: Add 'will_handle' callback support in xenbus_watch_path()")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202401121154.FI8jDGun-lkp@intel.com/Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20240112185903.83737-1-sj@kernel.orgSigned-off-by: Juergen Gross <jgross@suse.com>

drivers/xen/xenbus/xenbus_client.c

@@ -116,14 +116,15 @@ EXPORT_SYMBOL_GPL(xenbus_strstate);
  * @dev: xenbus device
  * @path: path to watch
  * @watch: watch to register
+ * @will_handle: events queuing determine callback
  * @callback: callback to register
  *
  * Register a @watch on the given path, using the given xenbus_watch structure
- * for storage, and the given @callback function as the callback.  On success,
- * the given @path will be saved as @watch->node, and remains the
- * caller's to free.  On error, @watch->node will
- * be NULL, the device will switch to %XenbusStateClosing, and the error will
- * be saved in the store.
+ * for storage, @will_handle function as the callback to determine if each
+ * event need to be queued, and the given @callback function as the callback.
+ * On success, the given @path will be saved as @watch->node, and remains the
+ * caller's to free.  On error, @watch->node will be NULL, the device will
+ * switch to %XenbusStateClosing, and the error will be saved in the store.
  *
  * Returns: %0 on success or -errno on error
  */
@@ -158,11 +159,13 @@ EXPORT_SYMBOL_GPL(xenbus_watch_path);
  * xenbus_watch_pathfmt - register a watch on a sprintf-formatted path
  * @dev: xenbus device
  * @watch: watch to register
+ * @will_handle: events queuing determine callback
  * @callback: callback to register
  * @pathfmt: format of path to watch
  *
  * Register a watch on the given @path, using the given xenbus_watch
- * structure for storage, and the given @callback function as the
+ * structure for storage, @will_handle function as the callback to determine if
+ * each event need to be queued, and the given @callback function as the
  * callback.  On success, the watched path (@path/@path2) will be saved
  * as @watch->node, and becomes the caller's to kfree().
  * On error, watch->node will be NULL, so the caller has nothing to