cfg80211/nl80211: add API for MAC address ACLs

Add API to enable drivers to implement MAC address based
access control in AP/P2P GO mode. Capable drivers advertise
this capability by setting the maximum number of MAC
addresses in such a list in wiphy->max_acl_mac_addrs.

An initial ACL may be given to the NL80211_CMD_START_AP
command and/or changed later with NL80211_CMD_SET_MAC_ACL.

Black- and whitelists are supported, but not simultaneously.

Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
[rewrite commit log, many cleanups]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Git-commit: 77765eaf5cfb6b8dd98ec8b54b411d74ff6095f1
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-fixed: 487410
Change-Id: I9593b887941be5efa5e96546ad92cd6c6bf8fb87
[duttus@codeaurora.org: resolved 3.4 backport issues]
Signed-off-by: Sunil Dutt <duttus@codeaurora.org>

Conflicts:

	include/net/cfg80211.h
	net/wireless/nl80211.c