mm/huge_memory.c: fix used-uninitialized

Fix used-uninitialized of `page'.

Fixes: dce7d10b ("mm/madvise: optimize lazyfreeing with mTHP in madvise_free")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202406260514.SLhNM9kQ-lkp@intel.com
Cc: Lance Yang <ioworker0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/huge_memory.c

@@ -2696,7 +2696,6 @@ static bool __discard_anon_folio_pmd_locked(struct vm_area_struct *vma,
 	struct mm_struct *mm = vma->vm_mm;
 	int ref_count, map_count;
 	pmd_t orig_pmd = *pmdp;
-	struct page *page;
 
 	if (folio_test_dirty(folio) || pmd_dirty(orig_pmd))
 		return false;
@@ -2732,7 +2731,7 @@ static bool __discard_anon_folio_pmd_locked(struct vm_area_struct *vma,
 		return false;
 	}
 
-	folio_remove_rmap_pmd(folio, page, vma);
+	folio_remove_rmap_pmd(folio, pmd_page(orig_pmd), vma);
 	zap_deposited_table(mm, pmdp);
 	add_mm_counter(mm, MM_ANONPAGES, -HPAGE_PMD_NR);
 	if (vma->vm_flags & VM_LOCKED)