Set channel and operating class in hostapd_fill_csa_settings()

Set channel and operating class in hostapd_fill_csa_settings()

The CSA channel and operating class values need to be set for all types
of channel switch (i.e., either if it's triggered by the control
interfaces or due to the GO-follows-STA flow). To do so, move the code
that sets them from the GO-follows-STA flow to the more generic
hostapd_fill_csa_settings() function.

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>