[media] media: davinci: vpif_capture: drop reserving memory for device

this patch drops reserving contigiuos memory for the device,
as now with CMA support there is no need of this.
This patch also prepares to removal of config_params.

Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>