mm/workingset: correct kernel-doc notations

Use the documented kernel-doc format to prevent kernel-doc warnings.

mm/workingset.c:256: warning: No description found for return value of 'workingset_eviction'
mm/workingset.c:285: warning: Function parameter or member 'folio' not described in 'workingset_refault'
mm/workingset.c:285: warning: Excess function parameter 'page' description in 'workingset_refault'

Link: https://lkml.kernel.org/r/20210808203153.10678-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/workingset.c

@@ -249,7 +249,7 @@ void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages)
  * @target_memcg: the cgroup that is causing the reclaim
  * @page: the page being evicted
  *
- * Returns a shadow entry to be stored in @page->mapping->i_pages in place
+ * Return: a shadow entry to be stored in @page->mapping->i_pages in place
  * of the evicted @page so that a later refault can be detected.
  */
 void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg)