staging: ath6kl: Fixing accidental overwriting of probed ssid list in the hardware

Fixing the code to avoid overwriting of the first index in the probed ssid
list maintained by the hardware. This index is used to store broadcast SSID.

Signed-off-by: Vipin Mehta <vmehta@atheros.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>