irqchip/loongson-liointc: Fix potential dead lock

In the function liointc_set_type(), we need to call the function
irq_gc_unlock_irqrestore() before returning.

Fixes: dbb15226 ("irqchip: Add driver for Loongson I/O Local Interrupt Controller")
Reported-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1594087972-21715-8-git-send-email-yangtiezhu@loongson.cn

drivers/irqchip/irq-loongson-liointc.c

@@ -114,6 +114,7 @@ static int liointc_set_type(struct irq_data *data, unsigned int type)
 		liointc_set_bit(gc, LIOINTC_REG_INTC_POL, mask, false);
 		break;
 	default:
+		irq_gc_unlock_irqrestore(gc, flags);
 		return -EINVAL;
 	}
 	irq_gc_unlock_irqrestore(gc, flags);