irqchip: Add the Alpine MSIX interrupt controller

This patch adds the Alpine MSIX interrupt controller driver.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Tsahee Zidenberg <tsahee@annapurnalabs.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 00bbec6..7e8c441 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -65,6 +65,12 @@
 	select GENERIC_IRQ_CHIP
 	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
 
+config ALPINE_MSI
+	bool
+	depends on PCI && PCI_MSI
+	select GENERIC_IRQ_CHIP
+	select PCI_MSI_IRQ_DOMAIN
+
 config ATMEL_AIC_IRQ
 	bool
 	select GENERIC_IRQ_CHIP