ARM: dts: exynos: Correct clocks for Exynos4 I2S module

"iis", "i2s_opclk0" and "i2s_opclk1" are standard clocks for Exynos4 I2S
hardware module, so they should be defined in .dtsi file not in the random
board .dts file.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>