USB: Avoid 20ms delay in EHCI resume

For function ehci_bus_resume()
- Added flag resume_needed
  No need to wait for 20ms if no port was suspended

- Change mdelay to msleep

- release and reacquire the spinlock around mdelay

Signed-off-by: vikram pandita <vikram.pandita@ti.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>