media: device property: Call fwnode_graph_get_endpoint_by_id() for fwnode->secondary

This function is used to find fwnode endpoints against a device. In
some instances those endpoints are software nodes which are children of
fwnode->secondary. Add support to fwnode_graph_get_endpoint_by_id() to
find those endpoints by recursively calling itself passing the ptr to
fwnode->secondary in the event no endpoint is found for the primary.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>