soundwire: bus: don't treat CMD_IGNORED as error on ClockStop

soundwire: bus: don't treat CMD_IGNORED as error on ClockStop

If a SoundWire link is enabled, but there are no Slave devices exposed
in firmware tables for this link, or no Slaves in ATTACHED or ALERT
mode, the CMD_IGNORED/-ENODATA error code on a broadcast write is
perfectly legit.

Filter this case to report errors and let the caller deal with the
CMD_IGNORED case.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200115000844.14695-11-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>