numa_nodes[] doesn't carry any information which isn't present in
numa_meminfo.  Each entry is simply min/max range of all the memblks
for the node.  This is not only redundant but also inaccurate when
memblks for different nodes interleave - for example,
find_node_by_addr() can return the wrong nodeid.

Kill numa_nodes[] and always use numa_meminfo instead.

* nodes_cover_memory() is renamed to numa_meminfo_cover_memory() and
  now operations on numa_meminfo and returns bool.

* setup_node_bootmem() needs min/max range.  Compute the range on the
  fly.  setup_node_bootmem() invocation is restructured to use outer
  loop instead of hardcoding the double invocations.

* find_node_by_addr() now operates on numa_meminfo.

* setup_physnodes() builds physnodes[] from memblks.  This will go
  away when emulation code is updated to use struct numa_meminfo.

This patch also makes the following misc changes.

* Clearing of nodes_add[] clearing is converted to memset().

* numa_add_memblk() in amd_numa_init() is moved down a bit for
  consistency.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shaohui Zheng <shaohui.zheng@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@linux.intel.com>