qoriq: dts: add missing reg property for WatchGuard Firebox M300

Set the reg property value based on node name "pca9547@77". This
patch fixes the following dtc warning:

watchguard-firebox-m300.dts:364.14-366.5: Warning (i2c_bus_reg): /soc@ffe000000/i2c@118000/pca9547@77: missing or empty reg property

Signed-off-by: Shiji Yang <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/18242
Signed-off-by: Hauke Mehrtens <[email protected]>

target/linux/qoriq/files/arch/powerpc/boot/dts/fsl/watchguard-firebox-m300.dts

@@ -362,6 +362,7 @@
 			reg = <0x32>;
 		};
 		pca9547@77 {
+			reg = <0x77>;
 			status = "disabled";
 		};
 	};