Fix OLBC non-HT AP detection to check channel

Fix OLBC non-HT AP detection to check channel

A non-HT capable AP on any channel could have triggered us to enable
protection regardless of own operating channel if the driver delivered
Beacon frames from other channels. The channel detection in ap_list is
not exactly ideal, but most cases can be handled by checking ap->channel
against the currently configured channel (or secondary channel in case
of HT40).

Signed-hostap: Jouni Malinen <j@w1.fi>