ASoC: reduce verbosity of error messages for sof-dai and sof-link

ASoC: reduce verbosity of error messages for sof-dai and sof-link

Recent changes result in multiple dmesg traces such as:

[ 14.410435] Audio Port: ASoC: error at snd_soc_link_startup on Audio
Port: 1

[ 14.410446] sst-mfld-platform sst-mfld-platform: ASoC: error at
snd_soc_dai_startup on media-cpu-dai: 1

These messages are not really errors, when dai and dai-link callbacks
return the value of e.g. snd_pcm_hw_constraint_single() the result is
"Positive if the value is changed, zero if it's not changed, or a
negative error code"

Add a simple test to skip the checks for positive returned values

Suggested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200529123613.13447-1-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>