iwlwifi: dbg_ini: add region to fill_header handler

Add iwl_fw_ini_region_cfg region struct to fill_header handler of
iwl_dump_ini_mem_ops. it is needed for future support in fifos dumping.

Signed-off-by: Shahar S Matityahu <shahar.s.matityahu@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>