Use the new ieee80211_rx_ni() function instead of ieee80211_rx(). Since we
use a workqueue to handle the RX path, we need to call the new function,
which disables bottom half handling. This patch fixes the NOHZ:
local_softirq_pending messages.
CC: Kalle Valo <kalle.valo@nokia.com> Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com> Reviewed-by: Kalle Valo <kalle.valo@nokia.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>