cfg80211: Convert del_station() callback to use a param struct

This makes it easier to add new parameters for the del_station calls
without having to modify all drivers that use this.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Git-commit: 89c771e5a62b856f4705f189892c489190edaec1
Git-repo: https://git.kernel.org/cgit/linux/kernel/git/linville/wireless-next.git


[asunka@codeaurora.org: resolve trivial merge conflicts and
add flag CFG80211_DEL_STA_V2 in include/net/cfg80211.h for
backward compatibility]
Change-Id: Ie3da671f0f41bf1d84dfd99cef87c06b91b522c5
CRs-Fixed: 743605
Signed-off-by: Anand N Sunkad <asunka@codeaurora.org>