[PATCH] USB: USB misc OHCI updates

[PATCH] USB: USB misc OHCI updates

Here are three minor OHCI changes:

* Turn off periodic dma transfers until they're needed.  Extra DMAs
  consume power, and can trigger problems on marginal systems.

* New module param "power_switching" (default false).  Many boards
  will have no problems with this mode.  It makes OHCI act more like
  most external hubs and like EHCI.

* Minor SMP cleanup affecting display-only usbfs statistics.

On one system, turning off the periodic DMAs made two of the four
active OHCI controllers work in cases that previously triggered
"Unrecoverable Error" IRQs.