[media] coda/imx-vdoa: constify structs

As warned by checkpatch:

	WARNING: struct of_device_id should normally be const
	#318: FILE: drivers/media/platform/coda/imx-vdoa.c:318:
	+static struct of_device_id vdoa_dt_ids[] = {

So, constify structs.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>