ayufan: dts: rockpro64: disable tx checksumming for gmac

Author: ayufan

arch/arm64/boot/dts/rockchip/rk3399-rockpro64.dts

@@ -878,6 +878,7 @@
 	phy-supply = <&vcc_phy>;
 	phy-mode = "rgmii";
 	clock_in_out = "input";
+	snps,force_thresh_dma_mode;
 	snps,reset-gpio = <&gpio3 15 GPIO_ACTIVE_LOW>;
 	snps,reset-active-low;
 	snps,reset-delays-us = <0 10000 50000>;