irqchip: vt8500: Convert arch-vt8500 to new irqchip infrastructure

This patch moves the arch-vt8500 irq code to drivers/irqchip and converts
it to use the new IRQCHIP_DECLARE and irqchip_init. This allows the removal
of some more functions from common.h

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Olof Johansson <olof@lixom.net>
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index acf9895..48fbdf9 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -12,3 +12,4 @@
 obj-$(CONFIG_RENESAS_INTC_IRQPIN)	+= irq-renesas-intc-irqpin.o
 obj-$(CONFIG_RENESAS_IRQC)		+= irq-renesas-irqc.o
 obj-$(CONFIG_VERSATILE_FPGA_IRQ)	+= irq-versatile-fpga.o
+obj-$(CONFIG_ARCH_VT8500)		+= irq-vt8500.o