usbnet: use jiffies in schedule_timeout(), not msecs

usbnet_terminate_urbs() uses schedule_timeout() with argument 3 msecs.
schedule_timeout() uses jiffies as argument, so convert msecs to jiffies
with msecs_to_jiffies().

Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>