wl1271-fw-2: Update to latest from linux-firmware

This updates the wl1271 firmware to the latest version
from linux-firmware (commit id 51a6242d).

From that commit log:
	Update FW for WL127x chip:
	 STA FW version 6.1.5.50.74
	 AP FW version 6.2.1.0.54

Note that later versions of firmware require ABI changes
(see commit id 14f515de).

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>