soundwire: add sdw_show_ping_status() helper

This helper provides an optional delay parameter to wait for devices
to resync in case of errors, and checks that devices are indeed
attached on the bus.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20220714011043.46059-4-yung-chuan.liao@linux.intel.com


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