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

drivers/soundwire/bus.c

@@ -922,8 +922,12 @@ int sdw_bus_clk_stop(struct sdw_bus *bus)
 	ret = sdw_bwrite_no_pm(bus, SDW_BROADCAST_DEV_NUM,
 			       SDW_SCP_CTRL, SDW_SCP_CTRL_CLK_STP_NOW);
 	if (ret < 0) {
-		dev_err(bus->dev,
-			"ClockStopNow Broadcast message failed %d", ret);
+		if (ret == -ENODATA)
+			dev_dbg(bus->dev,
+				"ClockStopNow Broadcast msg ignored %d", ret);
+		else
+			dev_err(bus->dev,
+				"ClockStopNow Broadcast msg failed %d", ret);
 		return ret;
 	}