ASoC: core: Return -ENOTSUPP from set_channel_map() if no operation provided

It makes it easier for common code to work with snd_soc_dai_set_channel_map()
by distinguishing between operation not being supported and an error.
This is done inline with others snd_soc_dai.* apis.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20190703123002.12427-1-srinivas.kandagatla@linaro.org


Signed-off-by: Mark Brown <broonie@kernel.org>