greybus: camera: Create and destroy data connection on demand

Creating the data connection at probe time makes it impossible to
support multiple inserted camera modules as they would all try to
establish a data connection to the same CPort on the AP side. Create and
destroy the data connection when configuring the streams instead, as a
single module can be streaming at a time.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Gjorgji Rosikopulos <grosikopulos@mm-sol.com>
Tested-by: Gjorgji Rosikopulos <grosikopulos@mm-sol.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>