[media] vb2: move dma_attrs to vb2_queue

[media] vb2: move dma_attrs to vb2_queue

Make the dma attributes struct part of vb2_queue. This greatly simplifies
the remainder of the patch series since the dma_contig alloc context is
now (as before) just a struct device pointer.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>