linux-firmware: wilc1000: add wilc1000 v15.4 FW

This commit add latest WILC1000 FW binary release v15.4. In latest
driver maintaining the API version info along with FW file name, so added
API version details in file name i.e. wilc1000_wifi_firmware-1.bin.
Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>

WHENCE

@@ -4503,6 +4503,8 @@ File: atmel/wilc1000_fw.bin
 File: atmel/wilc1000_ap_fw.bin
 File: atmel/wilc1000_p2p_fw.bin
 File: atmel/wilc1000_wifi_firmware.bin
+File: atmel/wilc1000_wifi_firmware-1.bin
+Version: 15.4
 
 License: Redistributable. See LICENSE.atmel for details