nslu2 startup with automatic fat-slug detection

[Marc Singer <elf@buici.com>]

I'm curious if we want to allow APEX to automatically detect more
memory on startup.  The code in APEX that reconfigures the memory
controller and then scans memory to determine the amount of memory
installed on the slug appears to be working properly in 64MiB and
128MiB slugs.  I'm working through testing the upgrade for APEX right
now.

The advantage of this is that people installing Debian would then be
able to run without a swap partition if they have already upgraded the
system memory.

We can always change the environment once the system is installed.
This is merely a convenience feature that will make for a better
install experience for users who are enhancing their slugs.

The only risk that I can see is if there is a memory configuration
that this code doesn't properly detect.  I've never tested a 4-chip
memory configuration myself, but I'm told by others that the existing
code *does* detect the second bank of memory chips.

Cheers