media: videobuf2: Explicitly state max size of planes

The plane size needs to be PAGE_ALIGNED, so it is not possible to have
sizes bigger than MAX_INT - PAGE_SIZE.

We already check for overflows when that happen:
 if (size < vb->planes[plane].length)
	goto free;

But it is good to explicitly state our max allowed value, in order to
align with the driver expectations.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>