iwmc3200wifi: replace netif_rx with netif_rx_ni

The patch uses netif_rx_ni() over netif_rx() to post buffers to
upper network code because it is always scheduled in a workqueue.
The problem was first observed from a dynamic ticks warning:

    "NOHZ: local_softirq_pending ..."

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>