ARM: dts: s3c2416: Fix xti node's missing reg property warning

Fix the DTC warning for xti node:

    arch/arm/boot/dts/s3c2416-smdk2416.dts:23.12-28.5:
        Warning (simple_bus_reg): /clocks/xti: missing or empty reg/ranges property

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>