dts: Cleanup warnings associated with interrupt controller nodes

We get several warnings of the form:

	Warning (unit_address_vs_reg): /cpus/arcv2-intc@0:
	node has a unit name, but no reg property

Fix by removing the unit address from the nodes.  Some cases we had a
reg property and a unit address for such interrupt controllers, in those
cases remove both the reg & unit address in the node name.

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>