modularization of setup_arch() for 2.4.20pre1

Please consider this patch for inclusion into the 2.4.20pre tree.
It was accepted into the 2.4.19pre6aa1, with slight modifications 
by Andrea that I have incorporated those changes into my patch.  
This patch, along with the modularization of mem_init, and the 
{node,zone}_start_paddr to {node,zone}_start_pfn change, are the
patches that my i386 discontigmem patch depends on.

This patch restructures setup_arch() for i386 to make it easier to
include the i386 numa changes (for CONFIG_DISCONTIGMEM) I've been 
working on.  It also makes setup_arch() easier to read.  

This patch does not depend on the other patches I'm submitting today, but 
my discontigmem patch does depend on this one. 

I've tested this patch on the following configurations: UP, SMP, SMP PAE, 
multiquad, multiquad PAE.

Any and all feedback regarding this patch is greatly appreciated.

Thanks,
Pat

-- 
Patricia Gaughen (gone@us.ibm.com)
IBM Linux Technology Center
http://www.ibm.com/linux/ltc/