irqchip/mtk-sysirq: Remove unnecessary barrier when configuring trigger

This prevent unnecessary visibility when configuring trigger type

Signed-off-by: Mars Cheng <mars.cheng@mediatek.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/drivers/irqchip/irq-mtk-sysirq.c b/drivers/irqchip/irq-mtk-sysirq.c
index 9ba969c..eeac512 100644
--- a/drivers/irqchip/irq-mtk-sysirq.c
+++ b/drivers/irqchip/irq-mtk-sysirq.c
@@ -57,7 +57,7 @@ static int mtk_sysirq_set_type(struct irq_data *data, unsigned int type)
 		value &= ~(1 << offset);
 	}
 
-	writel(value, base + reg_index * 4);
+	writel_relaxed(value, base + reg_index * 4);
 
 	data = data->parent_data;
 	ret = data->chip->irq_set_type(data, type);