staging: usbip: vhci_hcd: fixed suspend-resume loop

USB autosuspend suspends vhci_hcd. In this process hcd_bus_suspend gets
executed which puts vhci_hcd in suspend state and calls vhci_hub_status.
vhci_hub_status function checks hub state and if it is in suspend state,
usb_hcd_resume_root_hub gets executed which resumes hub and if hub is
idle, again autosuspend puts it in suspend state and this goes on.

vhci_hub_status should resume hub only when hub port is in suspend state
and hub port status has changed.

Signed-off-by: navin patidar <navinp@cdac.in>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>