libcamera: camera_sensor: Drop const on the return value of sizes()

The sizes() function returns a value, not a reference. There's no need
for it to be const.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

src/libcamera/camera_sensor.cpp

@@ -526,7 +526,7 @@ int CameraSensor::discoverAncillaryDevices()
  *
  * \return The supported frame sizes for \a mbusCode sorted in increasing order
  */
-const std::vector<Size> CameraSensor::sizes(unsigned int mbusCode) const
+std::vector<Size> CameraSensor::sizes(unsigned int mbusCode) const
 {
 	std::vector<Size> sizes;