mac80211: remove an unused parameter in ieee80211_rx_mgmt_probe_req().

This patch removes an unused parameter (rx_status) in
ieee80211_rx_mgmt_probe_req(),
in mlme.c.

Signed-off-by: Rami Rosen <ramirose@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>