wl18xx: add default configuration binary

The wl18xx-conf.bin contains a binary configuration that is used by
the driver to configure the firmware.
Signed-off-by: Luciano Coelho <coelho@ti.com>

WHENCE

@@ -1742,6 +1742,8 @@ File: ti-connectivity/wl18xx-fw.bin
 Version: 8.2.0.0.100
 File: ti-connectivity/wl18xx-fw-2.bin
 Version: 8.5.0.0.55
+File: ti-connectivity/wl18xx-conf.bin
+Version: 6/5
 
 Licence: See LICENCE.ti-connectivity for details.