media: v4l: vsp1: Fix header display list status check in continuous mode

media: v4l: vsp1: Fix header display list status check in continuous mode

To allow dual pipelines utilising two WPF entities when available, the
VSP was updated to support header-mode display list in continuous
pipelines.

A small bug in the status check of the command register causes the
second pipeline to be directly afflicted by the running of the first;
appearing as a perceived performance issue with stuttering display.

Fix the vsp1_dl_list_hw_update_pending() call to ensure that the read
comparison corresponds to the correct pipeline.

Fixes: eaf4bfad6ad8 ("v4l: vsp1: Add support for header display lists in continuous mode")
Cc: "Stable v4.14+" <stable@vger.kernel.org>
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>