media: v4l: vsp1: Turn frame end completion status into a bitfield

We will soon need to return more than a boolean completion status from
the vsp1_dlm_irq_frame_end() IRQ handler. Turn the return value into a
bitfield to prepare for that. No functional change is introduced here.

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