ACPI and amd are using separate nodes_parsed masks.  Add
{cpu|mem}_nodes_parsed and use them in all NUMA init methods.
Initialization of the masks and building node_possible_map are now
handled commonly by initmem_init().

dummy_numa_init() is updated to set node 0 on both masks.  While at
it, move the info messages from scan to init.
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>