media: atomisp: Replace queryctrl with query_ext_ctrl

media: atomisp: Replace queryctrl with query_ext_ctrl

The ioctl framework provides an emulator of queryctrl using
query_ext_ctrl.
Replace our implementation of queryctrl to support both.

Now that we are at it:
- Add comment about missing functionality.
- Remove superfluous clear of reserved[0].
- Remove ret var.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>