riscv: dts: rename the node name of dma

Rename the node name by the generic DMA naming
Signed-off-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/boot/dts/sifive/fu540-c000.dtsi

@@ -167,7 +167,7 @@ uart0: serial@10010000 {
 			clocks = <&prci FU540_PRCI_CLK_TLCLK>;
 			status = "disabled";
 		};
-		dma: dma@3000000 {
+		dma: dma-controller@3000000 {
 			compatible = "sifive,fu540-c000-pdma", "sifive,pdma0";
 			reg = <0x0 0x3000000 0x0 0x8000>;
 			interrupt-parent = <&plic0>;