soundwire: sysfs: have the driver core handle the creation of the device groups

The driver core supports the ability to handle the creation and removal
of device-specific sysfs files in a race-free manner. Take advantage of
that by converting this driver to use this by moving the sysfs
attributes into a group and assigning the dev_groups pointer to it.

Cc: Vinod Koul <[e-mail]>
Cc: Bard Liao <[e-mail]>
Cc: Pierre-Louis Bossart <[e-mail]>
Cc: Sanyog Kale <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>
Reviewed-by: Dan Williams <[e-mail]>
Tested-By: Vijendar Mukunda <[e-mail]>
Link: https://lore.kernel.org/r/2024013030-worsening-rocket-a3cb@gregkh
Signed-off-by: Vinod Koul <[e-mail]>

drivers/soundwire/bus_type.c

···
 	drv->driver.probe = sdw_drv_probe;
 	drv->driver.remove = sdw_drv_remove;
 	drv->driver.shutdown = sdw_drv_shutdown;
+	drv->driver.dev_groups = sdw_attr_groups;
 
 	return driver_register(&drv->driver);
 }

drivers/soundwire/sysfs_local.h

···
 /* basic attributes to report status of Slave (attachment, dev_num) */
 extern const struct attribute_group *sdw_slave_status_attr_groups[];
 
+/* attributes for all soundwire devices */
+extern const struct attribute_group *sdw_attr_groups[];
+
 /* additional device-managed properties reported after driver probe */
 int sdw_slave_sysfs_init(struct sdw_slave *slave);
 int sdw_slave_sysfs_dpn_init(struct sdw_slave *slave);

drivers/soundwire/sysfs_slave.c

···
 	.name = "dp0",
 };
 
-static const struct attribute_group *slave_groups[] = {
+const struct attribute_group *sdw_attr_groups[] = {
 	&slave_attr_group,
 	&sdw_slave_dev_attr_group,
 	&dp0_group,
···
 int sdw_slave_sysfs_init(struct sdw_slave *slave)
 {
 	int ret;
-
-	ret = devm_device_add_groups(&slave->dev, slave_groups);
-	if (ret < 0)
-		return ret;
 
 	if (slave->prop.source_ports || slave->prop.sink_ports) {
 		ret = sdw_slave_sysfs_dpn_init(slave);