iwlwifi: scan: support scan req FW API ver 13

1. Modify channel config flags to be used for legacy bands channels
   as well, to indicate SSIDs elements from ssidIEsArray.
2. Add new general flag.
3. Remove ssidNum from probe params.

Signed-off-by: Tova Mussai <tova.mussai@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>