USB: fix race in HCD removal

USB: fix race in HCD removal

This patch (as865) fixes a race in the HCD removal code discovered by
Milan Plzik.  Arrival of an interrupt after the root hub was
unregistered could cause the root-hub status timer to start up, even
after it was supposed to have been shut down.  The problem is fixed by
moving the del_timer_sync() call to after the HCD's stop() method, at
which time IRQ generation should be disabled.

Cc: Milan Plzik <[email protected]>
Signed-off-by: Alan Stern <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>