USB

USB
ehci-0306, iso, philips, speedups

      - adds preliminary highspeed ISO support
      - tweaks the driver to support the Philips EHCI
      - does less in the IRQ handler
      - avoids accessing one immutable PCI register

The ISO support should be enough to start writing
drivers, not that I know of any ISO devices that are
really available yet, but it's not fully cooked yet.

As a functional milestone, this means Linux now
handles all kinds of highspeed device I/O.  (But it
doesn't yet handle split periodic transactions, to
full or low speed devices through USB 2.0 hubs.)

Thanks to Rory Bolt for the non-ISO bits here!