arm: omap: irq: move irq.c to drivers/irqchip/

Just move the code over as it has no dependencies
on arch/arm/ anymore.

Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index b8632bf..9d539de 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -75,6 +75,11 @@
 	bool
 	select IRQ_DOMAIN
 
+config OMAP_IRQCHIP
+	bool
+	select GENERIC_IRQ_CHIP
+	select IRQ_DOMAIN
+
 config ORION_IRQCHIP
 	bool
 	select IRQ_DOMAIN