bmips: dts: nand: add missing address/size cells

Fixes the following warnings for Netgear DGND3700v2 and Comtrend VR-3032u:
[    1.059540] 7 fixed-partitions partitions found on MTD device brcmnand.0
[    1.066570] OF: Bad cell count for /ubus/nand@10000200/nandcs@0/partitions
[    1.073766] OF: Bad cell count for /ubus/nand@10000200/nandcs@0/partitions
[    1.081927] OF: Bad cell count for /ubus/nand@10000200/nandcs@0/partitions
[    1.089128] OF: Bad cell count for /ubus/nand@10000200/nandcs@0/partitions

Signed-off-by: Álvaro Fernández Rojas <[email protected]>

target/linux/bmips/dts/bcm63168-comtrend-vr-3032u.dts

@@ -162,6 +162,9 @@
 		nand-on-flash-bbt;
 		brcm,nand-oob-sector-size = <64>;
 
+		#address-cells = <1>;
+		#size-cells = <1>;
+
 		partitions {
 			compatible = "fixed-partitions";
 			#address-cells = <1>;

target/linux/bmips/dts/bcm6362-netgear-dgnd3700-v2.dts

@@ -210,6 +210,9 @@
 		nand-ecc-strength = <15>;
 		nand-on-flash-bbt;
 
+		#address-cells = <1>;
+		#size-cells = <1>;
+
 		partitions {
 			compatible = "fixed-partitions";
 			#address-cells = <1>;