mac80211: check size of channel switch IE when parsing

The channel switch IE has a fixed size, so we can
discard it in parsing if it's not the right size
and use the right struct pointer.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

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

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

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