soundwire: add new mclk_freq field for properties

To help pass platform-specific values, add a new field that can either
be set by the Master driver or read from firmware (BIOS/DT).
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190806005522.22642-11-pierre-louis.bossart@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

include/linux/soundwire/sdw.h

@@ -379,6 +379,7 @@ struct sdw_slave_prop {
  * @dynamic_frame: Dynamic frame shape supported
  * @err_threshold: Number of times that software may retry sending a single
  * command
+ * @mclk_freq: clock reference passed to SoundWire Master, in Hz.
  */
 struct sdw_master_prop {
 	u32 revision;
@@ -393,6 +394,7 @@ struct sdw_master_prop {
 	u32 default_col;
 	bool dynamic_frame;
 	u32 err_threshold;
+	u32 mclk_freq;
 };
 
 int sdw_master_read_prop(struct sdw_bus *bus);