ath79: specify "firmware" partition format for Netgear WNDR3800

It doesn't require trying parsers one by one.

Signed-off-by: Rafał Miłecki <[email protected]>

target/linux/ath79/dts/ar7161_netgear_wndr3800.dts

@@ -24,6 +24,7 @@
 	partition@70000 {
 		label = "firmware";
 		reg = <0x070000 0xf80000>;
+		compatible = "netgear,uimage";
 	};
 
 	art: partition@ff0000 {