dt-bindings: riscv: cpus: add ref to interrupt-controller

dt-bindings: riscv: cpus: add ref to interrupt-controller

removed the redundant properties for interrupt-controller
and provide reference to the riscv,cpu-intc.yaml which defines
the interrupt-controller. making the properties for riscv
interrupt-controller at a central place.

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Kanak Shilledar <kanakshilledar@gmail.com>
Link: https://lore.kernel.org/r/20240615021507.122035-3-kanakshilledar@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>