[MAC80211]: remove unused ioctls (1)

The ioctls

 * PRISM2_PARAM_ANTENNA_MODE
 * PRISM2_PARAM_STAT_TIME

are not used by hostapd or wpa_supplicant.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>