soundwire: bus: remove useless initialization

Cppcheck complains about a possible null pointer dereference, but it's
more like there is an unnecessary initialization before walking
through a list.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210302091122.13952-7-yung-chuan.liao@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/soundwire/bus.c

@@ -593,7 +593,7 @@ EXPORT_SYMBOL(sdw_write);
 /* called with bus_lock held */
 static struct sdw_slave *sdw_get_slave(struct sdw_bus *bus, int i)
 {
-	struct sdw_slave *slave = NULL;
+	struct sdw_slave *slave;
 
 	list_for_each_entry(slave, &bus->slaves, node) {
 		if (slave->dev_num == i)