link_id can be zero and if we have multiple controller instances
in a system like Qualcomm debugfs will end-up with duplicate namespace
resulting in incorrect debugfs entries.

Using bus-id and link-id combination should give a unique debugfs directory
entry and should fix below warning too.
"debugfs: Directory 'master-0' with parent 'soundwire' already present!"

Fixes: bf03473d ("soundwire: add debugfs support")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210907105332.1257-1-srinivas.kandagatla@linaro.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>