Fix hostapd segfault on beacon hint event

Fix hostapd segfault on beacon hint event

Commit 795baf773f6d53bae3cfae4df6edda63e5022344 ('hostapd: Filter
channel list updated events after country code change') uses the
EVENT_CHANNEL_LIST_CHANGED data pointer, but it updated only one of the
callers to provide that data. NL80211_CMD_REG_BEACON_HINT event was
still sending the event without the initiator data and resulted in NULL
pointer dereference, e.g., if a scan was run while hostapd was running
and the driver was in world roaming state and enabled a channel for
active scans.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>