media: ti-vpe: cal: fix enum_mbus_code/frame_size subdev arguments

Make sure that both enum_mbus_code() and enum_framesize() properly
populate the .which parameter member, otherwise -EINVAL is return
causing the subdev asynchronous registration handshake to fail.

Signed-off-by: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>