media: renesas: vsp1: Fix references to pad config

V4L2 subdev operations have moved from operating on a
v4l2_subdev_pad_config to a v4l2_subdev_state a long time ago. Fix
remaining incorrect references to pad config in function and variable
names.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>