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/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
index 11ccf0b..691d62a 100644
--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -86,6 +86,7 @@
 	select PINCTRL
 	select SOC_BUS
 	select TI_PRIV_EDMA
+	select OMAP_IRQCHIP
 	help
 	  Systems based on OMAP2, OMAP3, OMAP4 or OMAP5