(3/4) discontigmem support for i386 against 2.5.30

This patch restructures mem_init() for i386 to make it easier to
include the i386 numa changes (for CONFIG_DISCONTIGMEM) I've been 
working on.  A version of this patch is the in 2.4 aa tree.

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/