riscv: dts: starfive: add 'cpus' label to jh7110 and jh7100 soc dtsi

Add the 'cpus' label so that we can reference it in board dts files.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

arch/riscv/boot/dts/starfive/jh7100.dtsi

@@ -13,7 +13,7 @@ / {
 	#address-cells = <2>;
 	#size-cells = <2>;
 
-	cpus {
+	cpus: cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
 

arch/riscv/boot/dts/starfive/jh7110.dtsi

@@ -15,7 +15,7 @@ / {
 	#address-cells = <2>;
 	#size-cells = <2>;
 
-	cpus {
+	cpus: cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;