ons; note urbs are allocated and submitted for each activated interface.
- Modified sierra_startup() so that allocation of urbs happens whenever an
interface is activated (urb allocation is moved to sierra_open()).
- Modified sierra_shutdown() so that urbs are freed whenever an interface is
de-activated (urb freeing moved to sierra_close() as shown in previous patch
from the series)
- Removed unecessary data structure from sierra_port_private_data
- Suppress an entry in logs by not re-submitting an urb when usb_submit_urb()
returns -EPERM, as this shows that usb_kill_urb() is running (as suggested by
Oliver Neukum)

Signed-off-by: Elina Pasheva <epasheva@sierrawireless.com>
Signed-off-by: Alan Cox <alan.cox@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>