mm: use early_pfn_to_nid in register_page_bootmem_info_node

mm: use early_pfn_to_nid in register_page_bootmem_info_node

register_page_bootmem_info_node() is invoked in mem_init(), so it will
be called before page_alloc_init_late() if DEFERRED_STRUCT_PAGE_INIT is
enabled.  But, pfn_to_nid() depends on memmap which won't be fully setup
until page_alloc_init_late() is done, so replace pfn_to_nid() by
early_pfn_to_nid().

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Yang Shi <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>