It is not necessary to powerdown the ports on ehci_pci_reinit() when the
chip reset already did that. Removing this saves 20ms during restart
after poweroff paths (which OLPC uses a lot).
To ensure driver startup then behaves consistently, force a reset during
driver startup. (Not doing this was an accident of some previous changes
to the init sequence.)
Make the corresponding change in the PS3 support. It's not clear what
ehci-fsl should do here; it has similar code to the PS3.