media: v4l: subdev: Always compile sub-device state access functions

Compile sub-device state information access functions
v4l2_subdev_state_get_{format,crop,compose} unconditionally as they are
now also used by plain V4L2 drivers.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>