media: ti-vpe: cal: Add subdev s_power hooks

Because V4L2 still uses a specific way to manage power state of devices
that predates runtime PM, bridge driver should power on and off sub
device explicitly.

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>