media: uvcvideo: refactor uvc_ioctl_g_ext_ctrls

media: uvcvideo: refactor uvc_ioctl_g_ext_ctrls

We want to support fetching the min and max values with g_ext_ctrls,
this patch is a preparation for that.

Instead of abusing uvc_query_v4l2_ctrl(), add an extra parameter to
uvc_ctrl_get, so it can support fetching the default value.

Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Yunke Cao <yunkec@google.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Link: https://lore.kernel.org/r/20250203-uvc-roi-v17-6-5900a9fed613@chromium.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>