v4l: vsp1: Add pipe index argument to the VSP-DU API

In the H3 ES2.0 SoC the VSP2-DL instance has two connections to DU
channels that need to be configured independently. Extend the VSP-DU API
with a pipeline index to identify which pipeline the caller wants to
operate on.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Acked-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>