When detect radar in the process of SAP cac, SAP may choose another
DFS channel to switch and will do cac again, but still indicate
WLAN_SVC_DFS_CAC_START_IND with old DFS channel info to hostapd, it's
wrong. Issue is introduced by
'Change-Id: I0915ee78a97e5f27ce83c31cc673cb8820ae535b', due to this
change it will drop one time eSAP_CHANNEL_CHANGE_EVENT signal before
do cac start on new DFS channel, then operating_chan_freq for
hdd_ap_ctx can't be updated to new DFS channel timely.
Fix is to add one time eSAP_CHANNEL_CHANGE_EVENT signal before do cac
start in the process of channel switch.
Change-Id: I441e32e4ecd356834e66f97f2e2334966f48ec5d
CRs-Fixed: 2663539