media: uvcvideo: let v4l2_query_v4l2_ctrl() work with v4l2_query_ext_ctrl

v4l2_query_ext_ctrl contains information that is missing in
v4l2_queryctrl, like elem_size and elems.

With this change we can handle all the element_size information inside
uvc_ctrl.c.

Now that we are at it, remove the memset of the reserved fields, the
v4l2 ioctl handler should do that for us.

There is no functional change expected from this change.

Reviewed-by: Yunke Cao <yunkec@google.com>
Tested-by: Yunke Cao <yunkec@google.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Link: https://lore.kernel.org/r/20250203-uvc-roi-v17-13-5900a9fed613@chromium.org


Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>