ASoC: samsung: Use iio_get_channel_type() accessor.

ASoC: samsung: Use iio_get_channel_type() accessor.

struct iio_chan_spec is meant to be opaque to IIO consumer drivers
which should only use the interfaces in linux/iio/consumer.h.
Use the provided accessor function to find get the type of the
channel instead of directly reading it form the structure.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Link: https://lore.kernel.org/r/20220821160914.2207116-1-jic23@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>