memory-hotplug: fix wrong edge when hot add a new node

memory-hotplug: fix wrong edge when hot add a new node

When we add a new node, the edge of memory may be wrong.

e.g. system has 4 nodes, and node3 is movable, node3 mem:[24G-32G],

1. hotremove the node3,
2. then hotadd node3 with a part of memory, mem:[26G-30G],
3. call hotadd_new_pgdat()
        free_area_init_node()
                get_pfn_range_for_nid()
4. it will return wrong start_pfn and end_pfn, because we have not
update the memblock.

This patch also fixes a BUG_ON during hot-addition, please see
http://marc.info/?l=linux-kernel&m=142961156129456&w=2

Signed-off-by: Xishi Qiu <[email protected]>
Cc: Yasuaki Ishimatsu <[email protected]>
Cc: Kamezawa Hiroyuki <[email protected]>
Cc: Taku Izumi <[email protected]>
Cc: Tang Chen <[email protected]>
Cc: Gu Zheng <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>