USB: EHCI: merge all cases that disable the IO watchdog

This merges the vendor NEC case with the INTEL and AMD one,
as those 3 do exactly the same thing: disabling of the IO
watchdog.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>