Fix country code in wpa_supplicant AP mode Country element
country[2] needs to be set to ' ' instead of left to '\0' for the case
where wpa_supplicant sets up AP mode operations and includes the Country
element. Currently, this would be only for DFS channels. Without this,
the Beacon frames would go out with incorrect third octet in the country
code.
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>