ARM: dts: samsung: odroid-xu3: Move assigned-clock* properties to i2s0 node

The purpose of those assigned-clock-* properties is to configure clock for
for the I2S device so move them to respective node.

This suppresses the dtbs_check warning:
  arch/arm/boot/dts/exynos5422-odroidxu3.dt.yaml: sound: 'clocks' is a dependency of 'assigned-clocks'

Reported-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>