mm/memory_hotplug: remove reset_node_managed_pages() in hotadd_init_pgdat()

mm/memory_hotplug: remove reset_node_managed_pages() in hotadd_init_pgdat()

managed pages has already been set to 0 in free_area_init_core_hotplug(),
via zone_init_internals() on each zone.  It's pointless to reset again.

Furthermore, reset_node_managed_pages() no longer needs to be exposed
outside of mm/memblock.c.  Remove declaration in include/linux/memblock.h
and define it as static.

In addtion to this, the only caller of reset_node_managed_pages() is
reset_all_zones_managed_pages(), which is annotated with __init, so it
should be safe to also mark reset_node_managed_pages() as __init.

Link: https://lkml.kernel.org/r/20230607024548.1240-1-haifeng.xu@shopee.com
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>