USB: EHCI: update toggle state for linked QHs

This is an update to the "usb-ehci-update-toggle-state-for-linked-qhs"
patch.  Since an HCD's endpoint_reset method can be called in
interrupt context, it mustn't assume that interrupts are enabled or
that it can sleep.

So we revert to the original way of refreshing QHs' toggle bits.  Now
the endpoint_reset method merely clears the toggle flag in the device
structure (as was done before) and starts an async QH unlink.  When the
QH is linked again, after the unlink finishes and an URB is queued,
the qh_refresh() routine will update the QH's toggle bit.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: David <david@unsolicited.net>
CC: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>