When channel switch happens, driver wrapper's internal channel
information needs to be updated so that the new frequency will be used
in operations using drv->assoc_freq. Previously, only bss->freq was
updated and the new frequency was also indicated in the EVENT_CH_SWITCH
event. This could potentially leave out couple of cases that use
drv->assoc_freq at least as a fallback mechanism for getting the current
operating frequency.
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>