soundwire: bus: clarify dev_err/dbg device references

The SoundWire bus code confuses bus and Slave device levels for
dev_err/dbg logs. That's not impacting functionality but the accuracy
of kernel logs.

We should only use bus->dev for bus-level operations and handling of
Device0. For all other logs where the device number is not zero, we
should use &slave->dev to provide more precisions to the
user/integrator.

Reported-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210122070634.12825-10-yung-chuan.liao@linux.intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>