riscv: dts: Add DT support for SiFive FU540 PWM driver

Add the PWM DT node in SiFive FU540 soc-specific DT file.
Enable the PWM nodes in HiFive Unleashed board-specific DT file.
Signed-off-by: Yash Shah <yash.shah@sifive.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
[paul.walmsley@sifive.com: added chip-specific compatible string;
 dropped reg-names string from pwm1]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>

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

@@ -230,6 +230,24 @@ eth0: ethernet@10090000 {
 			#size-cells = <0>;
 			status = "disabled";
 		};
+		pwm0: pwm@10020000 {
+			compatible = "sifive,fu540-c000-pwm", "sifive,pwm0";
+			reg = <0x0 0x10020000 0x0 0x1000>;
+			interrupt-parent = <&plic0>;
+			interrupts = <42 43 44 45>;
+			clocks = <&prci PRCI_CLK_TLCLK>;
+			#pwm-cells = <3>;
+			status = "disabled";
+		};
+		pwm1: pwm@10021000 {
+			compatible = "sifive,fu540-c000-pwm", "sifive,pwm0";
+			reg = <0x0 0x10021000 0x0 0x1000>;
+			interrupt-parent = <&plic0>;
+			interrupts = <46 47 48 49>;
+			clocks = <&prci PRCI_CLK_TLCLK>;
+			#pwm-cells = <3>;
+			status = "disabled";
+		};
 
 	};
 };

arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts

@@ -85,3 +85,11 @@ phy0: ethernet-phy@0 {
 		reg = <0>;
 	};
 };
+
+&pwm0 {
+	status = "okay";
+};
+
+&pwm1 {
+	status = "okay";
+};