media: v4l2-subdev: Rename .init_cfg() operation to .init_state()

media: v4l2-subdev: Rename .init_cfg() operation to .init_state()

The subdev .init_cfg() operation is affected by two issues:

- It has long been extended to initialize a whole v4l2_subdev_state
  instead of just a v4l2_subdev_pad_config, but its name has stuck
  around.

- Despite operating on a whole subdev state and not being directly
  exposed to the subdev users (either in-kernel or through the userspace
  API), .init_cfg() is categorized as a subdev pad operation.

This participates in making the subdev API confusing for new developers.
Fix it by renaming the operation to .init_state(), and make it a subdev
internal operation.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Michael Riesch <michael.riesch@wolfvision.net> # for imx415
Acked-by: Shuah Khan <skhan@linuxfoundation.org> # for vimc
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
[Sakari Ailus: Resolved a conflict in Renesas vsp1 driver.]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>