USB: EHCI: notify usbcore about port resumes

This patch (as1650) adds calls to the new
usb_hcd_{start,end}_port_resume() functions to ehci-hcd.  Now EHCI
root hubs won't be runtime suspended while they are sending a resume
signal to one of their ports.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>