media: v4l2-subdev.h: add a BWS support in GMSL config

The GMSL supports different bus-widths (24 bit / 27 bit / 30 bit). How to
configure is different for devices. For some, it's boot-up configuration,
while it can be also configured through registers. Capture the property
as bus config because the configuration should align between source and
sink.

Signed-off-by: Hyun Kwon <hyun.kwon@xilinx.com>

include/media/v4l2-subdev.h

@@ -386,9 +386,15 @@ struct v4l2_mbus_csi2_cphy_config {
 /**
  * struct v4l2_mbus_gmsl_config - GMSL configuration
  * @vsync_active: polarity of vsync. active high = 1, active low = 0.
+ * @bws: three-level Bus-Width Select.
+ *	 '0' for 24 bit, '1' for 27 bit, '2' for 30 bit, '3' for invalid
+ *	 Note, in some devices, these modes may be represented differntly,
+ *	 For example, BWS is two-level ('0' is 24 bit, and '1' is 30 bit), and
+ *	 27 bit mode is when BWS is '0' and High-bandwidth mode = '1'.
  */
 struct v4l2_mbus_gmsl_config {
 	bool vsync_active : 1;
+	unsigned int bws : 2;
 };
 
 /**