soundwire: bus: split handling of Device0 events

Assigning a device number to a Slave will result in additional events
when it reports its status in a PING frame. There is no point in
dealing with all the other devices in a loop, this can be done when a
non-device0 event happens.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190725234032.21152-19-pierre-louis.bossart@linux.intel.com


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