irqchip: Move ARM GIC to drivers/irqchip

Now that we have drivers/irqchip, move GIC irqchip to drivers/irqchip. This
is necessary to share the GIC with arm and arm64.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 29b78c9..f2a9a07 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -2,5 +2,6 @@
 
 obj-$(CONFIG_ARCH_BCM2835)		+= irq-bcm2835.o
 obj-$(CONFIG_ARCH_SUNXI)		+= irq-sunxi.o
-obj-$(CONFIG_VERSATILE_FPGA_IRQ)	+= irq-versatile-fpga.o
 obj-$(CONFIG_ARCH_SPEAR3XX)		+= spear-shirq.o
+obj-$(CONFIG_ARM_GIC)			+= irq-gic.o
+obj-$(CONFIG_VERSATILE_FPGA_IRQ)	+= irq-versatile-fpga.o