dt-bindings: interrupt-controller: Add UltraRISC DP1000 PLIC

Add compatible strings for the PLIC found in UltraRISC DP1000 SoC.

The PLIC is part of the UR-CP100 core and has a hardware bug requiring
a workaround.

Signed-off-by: Charles Mirabile <cmirabil@redhat.com>
Signed-off-by: Lucas Zampieri <lzampier@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20251024083647.475239-3-lzampier@redhat.com

Author: Charles Mirabile

Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml

@@ -75,6 +75,9 @@ properties:
               - sophgo,sg2044-plic
               - thead,th1520-plic
           - const: thead,c900-plic
+      - items:
+          - const: ultrarisc,dp1000-plic
+          - const: ultrarisc,cp100-plic
       - items:
           - const: sifive,plic-1.0.0
           - const: riscv,plic0