mac80211: export IE splitting function

Export ieee80211_ie_split function, so it can be reused by
drivers which need to insert additional elements.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --cc include/net/mac80211.h
Simple merge

diff --cc net/mac80211/ieee80211_i.h
Simple merge

diff --cc net/mac80211/util.c
Simple merge