media: ov2740: Fix LINK_FREQ and PIXEL_RATE control value reporting

The driver dug the supported link frequency up from the V4L2 fwnode
endpoint and used it internally, but failed to report this in the
LINK_FREQ and PIXEL_RATE controls. Fix this.

Fixes: 0677a2d9 ("media: ov2740: Add support for 180 MHz link frequency")
Cc: stable@vger.kernel.org # for v6.8 and later
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>