Whilst looking at simplifying the implmentation of i386 initialisation code
I noticed the following.  This change allows these routines to be used in
both node based and flat memory models which allows more of the init code
to be common in these models.

Convert the default non-node based bootmem routines to use NODE_DATA(0).
This is semantically and functionally identical in any non-node
configuration as NODE_DATA(x) is defined as below.

#define NODE_DATA(nid)          (&contig_page_data)

For the node cases (CONFIG_NUMA and CONFIG_DISCONTIG_MEM) we can use these
non-node forms where all boot memory is defined on node 0.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>