media: rkisp1: Add struct rkisp1_params_buffer

media: rkisp1: Add struct rkisp1_params_buffer

Create the 'struct rkisp1_params_buffer' type that wraps a
vb2_v4l2_buffer to prepare to hold a copy of the parameters buffer that
will be used to cache the user-provided configuration buffer in the
following patches.

Replace usage of 'struct rkisp1_buffer' with 'struct
rkisp1_params_buffer' in rkisp1-params.c to prepare for that.

Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>