mm: mempolicy: use folio_alloc_mpol() in alloc_migration_target_by_mpol()

Convert to use folio_alloc_mpol() to make vma_alloc_folio_noprof() to use
folio throughout.

Link: https://lkml.kernel.org/r/20240515070709.78529-4-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/mempolicy.c

@@ -1211,7 +1211,6 @@ static struct folio *alloc_migration_target_by_mpol(struct folio *src,
 	struct migration_mpol *mmpol = (struct migration_mpol *)private;
 	struct mempolicy *pol = mmpol->pol;
 	pgoff_t ilx = mmpol->ilx;
-	struct page *page;
 	unsigned int order;
 	int nid = numa_node_id();
 	gfp_t gfp;
@@ -1235,8 +1234,7 @@ static struct folio *alloc_migration_target_by_mpol(struct folio *src,
 	else
 		gfp = GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL | __GFP_COMP;
 
-	page = alloc_pages_mpol(gfp, order, pol, ilx, nid);
-	return page_rmappable_folio(page);
+	return folio_alloc_mpol(gfp, order, pol, ilx, nid);
 }
 #else