[media] media/platform: convert drivers to use the new vb2_queue dev field

Stop using alloc_ctx and just fill in the device pointer.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Mikhail Ulyanov <mikhail.ulyanov@cogentembedded.com>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>