mm/mm_init.c: mark check_for_memory() as __init

The only caller of check_for_memory() is free_area_init(), which is
annotated with __init, so it should be safe to also mark the former as
__init.

Link: https://lkml.kernel.org/r/20230710093750.1294-1-haifeng.xu@shopee.comSigned-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/mm_init.c

@@ -1736,7 +1736,7 @@ static void __init free_area_init_node(int nid)
 }
 
 /* Any regular or high memory on that node ? */
-static void check_for_memory(pg_data_t *pgdat)
+static void __init check_for_memory(pg_data_t *pgdat)
 {
 	enum zone_type zone_type;