soundwire: slave: fix scanf format

fix cppcheck warning:

[drivers/soundwire/slave.c:145]: (warning) %x in format string (no. 1)
requires 'unsigned int *' but the argument type is 'signed int *'.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20191022233147.17268-1-pierre-louis.bossart@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/soundwire/slave.c

@@ -128,7 +128,8 @@ int sdw_of_find_slaves(struct sdw_bus *bus)
 	struct device_node *node;
 
 	for_each_child_of_node(bus->dev->of_node, node) {
-		int link_id, sdw_version, ret, len;
+		int link_id, ret, len;
+		unsigned int sdw_version;
 		const char *compat = NULL;
 		struct sdw_slave_id id;
 		const __be32 *addr;