[MIPS] Fix broken rm7000/rm9000 interrupt handling

Properly acknowledge RM7K and RM9K interrupts. Before this, interrupts were
permanently masked after their first occurrence, making them non-functional.
Signed-off-by: NThomas Koeller <thomas.koeller@baslerweb.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/kernel/irq-rm7000.c

@@ -33,6 +33,7 @@ static struct irq_chip rm7k_irq_controller = {
 	.mask = mask_rm7k_irq,
 	.mask_ack = mask_rm7k_irq,
 	.unmask = unmask_rm7k_irq,
+	.eoi	= unmask_rm7k_irq
 };
 
 void __init rm7k_cpu_irq_init(void)

arch/mips/kernel/irq-rm9000.c

@@ -75,6 +75,7 @@ static struct irq_chip rm9k_irq_controller = {
 	.mask = mask_rm9k_irq,
 	.mask_ack = mask_rm9k_irq,
 	.unmask = unmask_rm9k_irq,
+	.eoi	= unmask_rm9k_irq
 };
 
 static struct irq_chip rm9k_perfcounter_irq = {