mm/khugepaged: fix the address passed to notifier on testing young

Commit 8ee53820ed ("thp: mmu_notifier_test_young") introduced
mmu_notifier_test_young(), but we are passing the wrong address.
In xxx_scan_pmd(), the actual iteration address is "_address" not
"address".  We seem to misuse the variable on the very beginning.

Change it to the right one.

[akpm@linux-foundation.org fix whitespace, per everyone]
Link: https://lkml.kernel.org/r/20250822063318.11644-1-richard.weiyang@gmail.com
Fixes: 8ee53820ed ("thp: mmu_notifier_test_young")
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged.c

@@ -1417,8 +1417,8 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
 		 */
 		if (cc->is_khugepaged &&
 		    (pte_young(pteval) || folio_test_young(folio) ||
-		     folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
-								     address)))
+		     folio_test_referenced(folio) ||
+		     mmu_notifier_test_young(vma->vm_mm, _address)))
 			referenced++;
 	}
 	if (!writable) {