ipq40xx: specify "firmware" partition format for ZyXEL WRE6606

Specify firmware partition format by compatible string.

Signed-off-by: Christian Lamparter <[email protected]>

target/linux/ipq40xx/files-4.14/arch/arm/boot/dts/qcom-ipq4018-wre6606.dts

@@ -222,6 +222,7 @@
 			};
 
 			partition8@180000 {
+				compatible = "denx,fit";
 				label = "firmware";
 				reg = <0x00180000 0x00ce0000>;
 			};