mm/migrate.c: fix setting of cpupid on page migration twice against normal page

Commit 7851a45cd3 ("mm: numa: Copy cpupid on page migration") copies
over the cpupid at page migration time.  It is unnecessary to set it
again in alloc_misplaced_dst_page().

Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/migrate.c

@@ -1548,8 +1548,6 @@ static struct page *alloc_misplaced_dst_page(struct page *page,
 					  __GFP_NOMEMALLOC | __GFP_NORETRY |
 					  __GFP_NOWARN) &
 					 ~GFP_IOFS, 0);
-	if (newpage)
-		page_cpupid_xchg_last(newpage, page_cpupid_last(page));
 
 	return newpage;
 }