irqchip/sifive-plic: Use riscv_get_intc_hwnode() to get parent fwnode

The RISC-V INTC irqdomain is always the parent irqdomain of SiFive PLIC
so use riscv_get_intc_hwnode() to get the parent fwnode similar to other
RISC-V drivers which use local interrupts.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240222094006.1030709-5-apatel@ventanamicro.com

drivers/irqchip/irq-sifive-plic.c

@@ -423,6 +423,7 @@ static int plic_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	unsigned long plic_quirks = 0;
 	struct plic_handler *handler;
+	struct irq_domain *domain;
 	struct plic_priv *priv;
 	bool cpuhp_setup;
 	unsigned int cpu;
@@ -502,11 +503,11 @@ static int plic_probe(struct platform_device *pdev)
 		}
 
 		/* Find parent domain and register chained handler */
-		if (!plic_parent_irq && irq_find_host(parent.np)) {
-			plic_parent_irq = irq_of_parse_and_map(to_of_node(dev->fwnode), i);
+		domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(), DOMAIN_BUS_ANY);
+		if (!plic_parent_irq && domain) {
+			plic_parent_irq = irq_create_mapping(domain, RV_IRQ_EXT);
 			if (plic_parent_irq)
-				irq_set_chained_handler(plic_parent_irq,
-							plic_handle_irq);
+				irq_set_chained_handler(plic_parent_irq, plic_handle_irq);
 		}
 
 		/*