ASoC: samsung: i2s: Move opclk data to common driver data structure

The clock for generating I2S signals is also common for both CPU DAIs
so move it to the driver's common data structure.

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