Silence irrelevant warning on 32 bit platforms.

[bdragon]

Summary

In r309092, a warning was added to note when the PhysicalUpperBound register isn't implemented, to make it more obvious that remote debugging will only be able to access the first 4G of physical RAM.

However, on 32 bit platforms, we shouldn't even care in the first place, since the rest of the system can't address more than that either.

Removes an annoying warning I am experiencing when testing firewire on my iBook G4.

[jhibbits]

sys/dev/firewire/fwohci.c

1865

I think it'd be better to instead make it check on Maxmem, and only display the warning if ptoa(Maxmem) > 2**32. 32-bit platforms can have more than 4GB RAM, however unlikely that may be.

[imp]

sys/dev/firewire/fwohci.c

1865

It's not unlikely at all. Many late i386 machines have 4GB of RAM, but part of that is mapped above the 4GB boundary.

[jhibbits]

See above comment. It shouldn't be gated on LP64

[bdragon]

Abandoning, after further thought, I'd really rather have it there so I know what the interface is capable of anyway.