ARM: mxs: move icoll driver into drivers/irqchip

Move icoll.c into drivers/irqchip as irq-mxs.c, and along with the
renaming, change the driver to use IRQCHIP_DECLARE.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 98e3b87..9d8f4f1 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -2,6 +2,7 @@
 
 obj-$(CONFIG_ARCH_BCM2835)		+= irq-bcm2835.o
 obj-$(CONFIG_ARCH_EXYNOS)		+= exynos-combiner.o
+obj-$(CONFIG_ARCH_MXS)			+= irq-mxs.o
 obj-$(CONFIG_METAG)			+= irq-metag-ext.o
 obj-$(CONFIG_METAG_PERFCOUNTER_IRQS)	+= irq-metag.o
 obj-$(CONFIG_ARCH_SUNXI)		+= irq-sunxi.o