ipq40xx: nbg6617: switch to upstream boardfile variant

The NBG6617's boardfile was merged and this device can
now switch to the upstream ath10k board-2.bin.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

target/linux/ipq40xx/files-4.14/arch/arm/boot/dts/qcom-ipq4018-nbg6617.dts

@@ -301,10 +301,12 @@
 
 &wifi0 {
 	status = "okay";
+	qcom,ath10k-calibration-variant = "ZyXEL-NBG6617";
 };
 
 &wifi1 {
 	status = "okay";
+	qcom,ath10k-calibration-variant = "ZyXEL-NBG6617";
 };
 
 &usb3_ss_phy {