ASoC: samsung: i2s: Update clock-output-names property documentation

The clock-output-names property is marked as deprecated. While at it,
and few typos are fixed.

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