arm: dts: vexpress: Drop unused properties from motherboard node

Drop the '#interrupt-cells' property in the motherboard node which has no
effect as the node is neither an interrupt-controller or interrupt-map
(that's in the parent node).

Drop 'model' as it is not used by software nor documented.

Drop 'arm,v2m-memory-map' as it is not used by software. The purpose was
to describe which memory map, but that's all described by the DT
already.

Link: https://lore.kernel.org/r/[e-mail]
Cc: Andre Przywara <[e-mail]>
Cc: Sudeep Holla <[e-mail]>
Cc: Linus Walleij <[e-mail]>
Reviewed-by: Linus Walleij <[e-mail]>
Signed-off-by: Rob Herring <[e-mail]>
Signed-off-by: Sudeep Holla <[e-mail]>

arch/arm/boot/dts/vexpress-v2m-rs1.dtsi

···
 
 	bus@8000000 {
 		motherboard-bus {
-			model = "V2M-P1";
 			arm,hbi = <0x190>;
 			arm,vexpress,site = <0>;
-			arm,v2m-memory-map = "rs1";
 			compatible = "arm,vexpress,v2m-p1", "simple-bus";
 			#address-cells = <2>; /* SMB chipselect number and offset */
 			#size-cells = <1>;
-			#interrupt-cells = <1>;
 			ranges;
 
 			nor_flash: flash@0 {

arch/arm/boot/dts/vexpress-v2m.dtsi

···
 / {
 	bus@4000000 {
 		motherboard {
-			model = "V2M-P1";
 			arm,hbi = <0x190>;
 			arm,vexpress,site = <0>;
 			compatible = "arm,vexpress,v2m-p1", "simple-bus";
 			#address-cells = <2>; /* SMB chipselect number and offset */
 			#size-cells = <1>;
-			#interrupt-cells = <1>;
 			ranges;
 
 			flash@0,00000000 {

arch/arm64/boot/dts/arm/foundation-v8.dtsi

···
 
 	bus@8000000 {
 		compatible = "arm,vexpress,v2m-p1", "simple-bus";
-		arm,v2m-memory-map = "rs1";
 		#address-cells = <2>; /* SMB chipselect number and offset */
 		#size-cells = <1>;
 

arch/arm64/boot/dts/arm/juno-motherboard.dtsi

···
 			compatible = "arm,vexpress,v2p-p1", "simple-bus";
 			#address-cells = <2>;  /* SMB chipselect number and offset */
 			#size-cells = <1>;
-			#interrupt-cells = <1>;
 			ranges;
-			model = "V2M-Juno";
 			arm,hbi = <0x252>;
 			arm,vexpress,site = <0>;
-			arm,v2m-memory-map = "rs1";
 
 			flash@0 {
 				/* 2 * 32MiB NOR Flash memory mounted on CS0 */

arch/arm64/boot/dts/arm/rtsm_ve-motherboard.dtsi

···
 
 	bus@8000000 {
 		motherboard-bus {
-			arm,v2m-memory-map = "rs1";
 			compatible = "arm,vexpress,v2m-p1", "simple-bus";
 			#address-cells = <2>; /* SMB chipselect number and offset */
 			#size-cells = <1>;
-			#interrupt-cells = <1>;
 			ranges;
 
 			flash@0 {