ASoC: samsung: i2s: Get rid of a static spinlock

This patch makes the spinlock serializing access to the primary/secondary
PCM a per I2S controller lock, rather than a global one. There is no need
to have a global lock across multiple I2S controllers in the SoC.

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