wl18xx: update firmware file, remove conf file

- Firmware file was updated (8.9.0.0.39), includes bug fixes and improvements.
    - Configuration binary removed, it is no longer fits all releases.
      Moreover it should be configured per HW platform.
      More information can found in here :
      http://processors.wiki.ti.com/index.php/Open_Source_Wireless_Connectivity_wlconf

Signed-off-by: Yaniv Machani <yanivma@ti.com>

WHENCE

@@ -1997,9 +1997,7 @@ Version: 8.5.0.0.55
 File: ti-connectivity/wl18xx-fw-3.bin
 Version: 8.8.0.0.13
 File: ti-connectivity/wl18xx-fw-4.bin
-Version: 8.9.0.0.17
+Version: 8.9.0.0.39
-File: ti-connectivity/wl18xx-conf.bin
-Version: 6/5
 
 Licence: See LICENCE.ti-connectivity for details.