mm: make dump_page() take a const argument

Now that __dump_page() takes a const argument, we can make dump_page()
take a const struct page too.

Link: https://lkml.kernel.org/r/20240227192337.757313-6-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/mmdebug.h

@@ -10,7 +10,7 @@ struct vm_area_struct;
 struct mm_struct;
 struct vma_iterator;
 
-void dump_page(struct page *page, const char *reason);
+void dump_page(const struct page *page, const char *reason);
 void dump_vma(const struct vm_area_struct *vma);
 void dump_mm(const struct mm_struct *mm);
 void vma_iter_dump_tree(const struct vma_iterator *vmi);

mm/debug.c

@@ -149,7 +149,7 @@ static void __dump_page(const struct page *page)
 	__dump_folio(foliop, &precise, pfn, idx);
 }
 
-void dump_page(struct page *page, const char *reason)
+void dump_page(const struct page *page, const char *reason)
 {
 	if (PagePoisoned(page))
 		pr_warn("page:%p is uninitialized and poisoned", page);