plic: irq: Set IRQCHIP_EOI_THREADED in PREEMPT_RT case

In ipms can device or other device, interrupt is trigger by level.
in PREEMPT_RT case. irq handle is in thread, If not set
IRQCHIP_EOI_THREADED, device irq in PLIC is cleared first, but
device irq reg is not clear, So the interrupt will be triggered
again, IRQCHIP_EOI_THREADED will clear device PLIC IRQ status
after clear device irq reg.

Signed-off-by: Minda Chen <minda.chen@starfivetech.com>

drivers/irqchip/irq-sifive-plic.c

@@ -198,6 +198,9 @@ static struct irq_chip plic_edge_chip = {
 #endif
 	.irq_set_type	= plic_irq_set_type,
 	.flags		= IRQCHIP_SKIP_SET_WAKE |
+#ifdef CONFIG_PREEMPT_RT
+			  IRQCHIP_EOI_THREADED |
+#endif
 			  IRQCHIP_AFFINITY_PRE_STARTUP,
 };
 
@@ -213,6 +216,9 @@ static struct irq_chip plic_chip = {
 #endif
 	.irq_set_type	= plic_irq_set_type,
 	.flags		= IRQCHIP_SKIP_SET_WAKE |
+#ifdef CONFIG_PREEMPT_RT
+			  IRQCHIP_EOI_THREADED |
+#endif
 			  IRQCHIP_AFFINITY_PRE_STARTUP,
 };