There are two warnings that are due to functions that has long
gone:

	Documentation/media/kapi/v4l2-subdev.rst:417: WARNING: c:func reference target not found: v4l2_i2c_new_subdev_cfg
	Documentation/media/kapi/v4l2-subdev.rst:436: WARNING: c:func reference target not found: v4l2_i2c_new_probed_subdev

Update the documentation to remove those.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>