soundwire: Add missing EXPORT for sdw_slave_type

include/sdw_type.h provides the function is_sdw_slave() which
requires sdw_slave_type. But sdw_slave_type was not exported.

Signed-off-by: Richard Fitzgerald <[e-mail]>
Acked-by: Vinod Koul <[e-mail]>
Reviewed-by: Pierre-Louis Bossart <[e-mail]>
Reviewed-by: Charles Keepax <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/soundwire/slave.c

···
 	.release =	sdw_slave_release,
 	.uevent =	sdw_slave_uevent,
 };
+EXPORT_SYMBOL_GPL(sdw_slave_type);
 
 int sdw_slave_add(struct sdw_bus *bus,
 		  struct sdw_slave_id *id, struct fwnode_handle *fwnode)