This patch should improve behavior of the EHCI driver,
particularly on VIA hardware.

  - A more careful reading of the EHCI spec turns up
    requirements not to change this register's value
    while the async schedule is enabled.  That means
    in effect that it must never point to a QH that'd
    get unlinked ... driver now uses a dedicated QH.

  - Disables async schedule a bit faster:  after 50msec
    idle, not 330msec idle.

  - Streamline the "can't init memory" failure path.

  - Start to use the dev_dbg()/dev_info()/... macros
    in more places.

This version acts a bunch happier than the previous
version, removing some failure modes I could never
quite convince myself were hardware (they weren't!)
I suspect it'll remove a lot of the "it hangs" failures
that some folk have reported (mostly on 2.4 though).