drivers/base/node: remove register_mem_block_under_node_early()

drivers/base/node: remove register_mem_block_under_node_early()

The function register_mem_block_under_node_early() is no longer used, as
register_memory_blocks_under_node_early() now handles memory block
registration during early boot.

Removed register_mem_block_under_node_early() and get_nid_for_pfn(), the
latter was only used by the former.

Link: https://lkml.kernel.org/r/22e0c5d20f1d33a91d0436ad22d96628cf084d1b.1748452242.git.donettom@linux.ibm.com
Signed-off-by: Donet Tom <donettom@linux.ibm.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>