riscv: dts: microchip: re-add pdma to mpfs device tree

PolarFire SoC /does/ have a SiFive pdma, despite what I suggested as a
conflict resolution to Zong. Somehow the entry fell through the cracks
between versions of my dt patches, so re-add it with Zong's updated
compatible & dma-channels property.

Fixes: c5094f37 ("riscv: dts: microchip: refactor icicle kit device tree")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

arch/riscv/boot/dts/microchip/mpfs.dtsi

@@ -192,6 +192,15 @@ plic: interrupt-controller@c000000 {
 			riscv,ndev = <186>;
 		};
 
+		pdma: dma-controller@3000000 {
+			compatible = "sifive,fu540-c000-pdma", "sifive,pdma0";
+			reg = <0x0 0x3000000 0x0 0x8000>;
+			interrupt-parent = <&plic>;
+			interrupts = <5 6>, <7 8>, <9 10>, <11 12>;
+			dma-channels = <4>;
+			#dma-cells = <1>;
+		};
+
 		clkcfg: clkcfg@20002000 {
 			compatible = "microchip,mpfs-clkcfg";
 			reg = <0x0 0x20002000 0x0 0x1000>, <0x0 0x3E001000 0x0 0x1000>;