media: v4l2-fwnode: Make bus configuration a struct

The bus specific parameters were a union. This made providing bus specific
defaults impossible as the memory used to store the defaults for multiple
different busses was the same.

Make it struct instead. It's not large so the size isn't really an issue.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

include/media/v4l2-fwnode.h

@@ -78,7 +78,7 @@ struct v4l2_fwnode_bus_mipi_csi1 {
  * struct v4l2_fwnode_endpoint - the endpoint data structure
  * @base: fwnode endpoint of the v4l2_fwnode
  * @bus_type: bus type
- * @bus: union with bus configuration data structure
+ * @bus: bus configuration data structure
  * @bus.parallel: embedded &struct v4l2_fwnode_bus_parallel.
  *		  Used if the bus is parallel.
  * @bus.mipi_csi1: embedded &struct v4l2_fwnode_bus_mipi_csi1.
@@ -99,7 +99,7 @@ struct v4l2_fwnode_endpoint {
 	 * v4l2_fwnode_endpoint_parse()
 	 */
 	enum v4l2_mbus_type bus_type;
-	union {
+	struct {
 		struct v4l2_fwnode_bus_parallel parallel;
 		struct v4l2_fwnode_bus_mipi_csi1 mipi_csi1;
 		struct v4l2_fwnode_bus_mipi_csi2 mipi_csi2;