irqchip: Add a driver for the Microsemi Ocelot controller

The Microsemi Ocelot SoC has a pretty simple IRQ controller in its ICPU
block. Add a driver for it.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/Kconfig

@@ -286,6 +286,11 @@ config IRQ_MXS
 	select IRQ_DOMAIN
 	select STMP_DEVICE
 
+config MSCC_OCELOT_IRQ
+	bool
+	select IRQ_DOMAIN
+	select GENERIC_IRQ_CHIP
+
 config MVEBU_GICP
 	bool