This is a straightforward change matching ones sent in
for ehci (last month) and ohci (earlier this week).

It abstracts the reset operation into something that's
called before the pci glue does much to the hardware.

It also arranges to kick the BIOS off the hardware before
it resets it (not after) ... so there's no confusion at
any time about what driver "owns" that hardware.  (Again
matching what ehci and ohci drivers do.)