soundwire: add lane_used_bandwidth in struct sdw_bus

To support multi-lane, we need to know how much bandwidth
is used on each lane. And to use the lane that has enough
bandwidth.

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>

include/linux/soundwire/sdw.h

@@ -889,6 +889,7 @@ struct sdw_master_ops {
  * @multi_link: Store bus property that indicates if multi links
  * are supported. This flag is populated by drivers after reading
  * appropriate firmware (ACPI/DT).
+ * @lane_used_bandwidth: how much bandwidth in bits per second is used by each lane
  */
 struct sdw_bus {
 	struct device *dev;
@@ -920,6 +921,7 @@ struct sdw_bus {
 	struct dentry *debugfs;
 #endif
 	bool multi_link;
+	unsigned int lane_used_bandwidth[SDW_MAX_LANES];
 };
 
 int sdw_bus_master_add(struct sdw_bus *bus, struct device *parent,