Instead of keeping track of all those special cases where
VLAN interfaces have no bss_conf.chandef, just make sure
they have the same as the AP interface they belong to.
Among others, this fixes a crash getting a VLAN's channel
from userspace since a NULL channel is returned as a good
result (return value 0) for VLANs since the commit below.
Cc: stable@vger.kernel.org [3.18 only] Fixes: c12bc4885f4b3 ("mac80211: return the vif's chandef in ieee80211_cfg_get_channel()") Signed-off-by: Felix Fietkau <nbd@openwrt.org>
[rewrite commit log] Signed-off-by: Johannes Berg <johannes.berg@intel.com>