media: v4l2-core: Introduce v4l2_query_ext_ctrl_to_v4l2_queryctrl

We use this logic in a couple of places. Refactor into a function.
No functional change expected from this patch.

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>