cdx: Register cdx bus as a device on cdx subsystem

While scanning for CDX devices, register newly discovered bus as a
cdx device. CDX device attributes are visible based on device type.

Signed-off-by: Abhijit Gangurde <abhijit.gangurde@amd.com>
Link: https://lore.kernel.org/r/20231017160505.10640-5-abhijit.gangurde@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/cdx/cdx_bus.h

@@ -88,6 +88,7 @@ struct cdx_controller {
  * @dma_mask: Default DMA mask
  * @flags: CDX device flags
  * @req_id: Requestor ID associated with CDX device
+ * @is_bus: Is this bus device
  * @driver_override: driver name to force a match; do not set directly,
  *                   because core frees it; use driver_set_override() to
  *                   set or clear it.
@@ -104,6 +105,7 @@ struct cdx_device {
 	u64 dma_mask;
 	u16 flags;
 	u32 req_id;
+	bool is_bus;
 	const char *driver_override;
 };