irqchip/irq-mst: Add MStar interrupt controller support

Add MStar interrupt controller support using hierarchy irq
domain.

Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Tested-by: Daniel Palmer <daniel@thingy.jp>
Link: https://lore.kernel.org/r/20200902063344.1852-2-mark-pk.tsai@mediatek.com
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 133f9c4..e2688a6 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -111,3 +111,4 @@
 obj-$(CONFIG_LOONGSON_HTVEC)		+= irq-loongson-htvec.o
 obj-$(CONFIG_LOONGSON_PCH_PIC)		+= irq-loongson-pch-pic.o
 obj-$(CONFIG_LOONGSON_PCH_MSI)		+= irq-loongson-pch-msi.o
+obj-$(CONFIG_MST_IRQ)			+= irq-mst-intc.o