x86: optimize resource lookups for ioremap

We have a large university system in the UK that is experiencing very long
delays modprobing the driver for a specific I/O device.  The delay is from
8-10 minutes per device and there are 31 devices in the system.  This 4 to
5 hour delay in starting up those I/O devices is very much a burden on the
customer.

There are two causes for requiring a restart/reload of the drivers.  First
is periodic preventive maintenance (PM) and the second is if any of the
devices experience a fatal error.  Both of these trigger this excessively
long delay in bringing the system back up to full capability.

The problem was tracked down to a very slow IOREMAP operation and the
excessively long ioresource lookup to insure that the user is not
attempting to ioremap RAM.  These patches provide a speed up to that
function.

The modprobe time appears to be affected quite a bit by previous activity
on the ioresource list, which I suspect is due to cache preloading.  While
the overall impro...