riscv: dts: microchip: add missing compatibles for clint and plic

The Microchip Icicle kit uses SiFive E51 and U54 cores, so it looks that
also Core Local Interruptor and Platform-Level Interrupt Controller are
coming from SiFive.  Add proper compatibles to silence dtbs_check
warnings:

  clint@2000000: compatible:0: 'sifive,clint0' is not one of ['sifive,fu540-c000-clint', 'canaan,k210-clint']
  interrupt-controller@c000000: compatible:0: 'sifive,plic-1.0.0' is not one of ['sifive,fu540-c000-plic', 'canaan,k210-plic']
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20210920130412.145231-1-krzysztof.kozlowski@canonical.com

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

@@ -161,7 +161,7 @@ cache-controller@2010000 {
 		};
 
 		clint@2000000 {
-			compatible = "sifive,clint0";
+			compatible = "sifive,fu540-c000-clint", "sifive,clint0";
 			reg = <0x0 0x2000000 0x0 0xC000>;
 			interrupts-extended = <&cpu0_intc 3 &cpu0_intc 7
 						&cpu1_intc 3 &cpu1_intc 7
@@ -172,7 +172,7 @@ &cpu3_intc 3 &cpu3_intc 7
 
 		plic: interrupt-controller@c000000 {
 			#interrupt-cells = <1>;
-			compatible = "sifive,plic-1.0.0";
+			compatible = "sifive,fu540-c000-plic", "sifive,plic-1.0.0";
 			reg = <0x0 0xc000000 0x0 0x4000000>;
 			riscv,ndev = <186>;
 			interrupt-controller;