[PATCH] ieee80211: Remove WIRELESS_EXT < 17 support

No need to maintain support for WIRELESS_EXT < 17 since this kernel
tree is already using WIRELESS_EXT 18.

Signed-off-by: Jouni Malinen <jkmaline@cc.hut.fi>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>