ASoC: samsung: i2s: Drop spinlock pointer from i2s_dai data structure

As we now have the 'priv' pointer in most of the places we can use
priv->lock directly, dropping extra indirection in the SFR region
spinlock access.

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