The VSP supports both header and headerless display lists. The latter is
easier to use when the VSP feeds data directly to the DU in continuous
mode, and the driver thus uses headerless display lists for DU operation
and header display lists otherwise.

Headerless display lists are only available on WPF.0. This has never
been an issue so far, as only WPF.0 is connected to the DU. However, on
H3 ES2.0, the VSP-DL instance has both WPF.0 and WPF.1 connected to the
DU. We thus can't use headerless display lists unconditionally for DU
operation.

Implement support for continuous mode with header display lists, and use
it for DU operation on WPF outputs that don't support headerless mode.
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>