Send frequency changed event to framework

When supplicant receives the channel change event
(NL80211_CMD_CH_SWITCH_NOTIFY) from driver, send
the new operating frequency information to framework.

Bug: 202758240
Test: Manually triggered channel switch through hostapd command
    and verified the new frequency in p2p group info logs
Change-Id: I05f10077ac497b934eb2c0560e179cdf4ed1497f
5 files changed