mm/page_alloc: put __free_pages_core() in __meminit section

__free_pages_core() is only used in bootmem init and hot-add memory init
path.  Let's put it in __meminit section.

Link: https://lkml.kernel.org/r/20240706061615.30322-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memory_hotplug.c

@@ -628,7 +628,8 @@ int restore_online_page_callback(online_page_callback_t callback)
 }
 EXPORT_SYMBOL_GPL(restore_online_page_callback);
 
-void generic_online_page(struct page *page, unsigned int order)
+/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
+void __ref generic_online_page(struct page *page, unsigned int order)
 {
 	__free_pages_core(page, order, MEMINIT_HOTPLUG);
 }

mm/page_alloc.c

@@ -1219,7 +1219,7 @@ static void __free_pages_ok(struct page *page, unsigned int order,
 	__count_vm_events(PGFREE, 1 << order);
 }
 
-void __free_pages_core(struct page *page, unsigned int order,
+void __meminit __free_pages_core(struct page *page, unsigned int order,
 		enum meminit_context context)
 {
 	unsigned int nr_pages = 1 << order;