ipa: rkisp1: Fill AGC and AWB metadata

Fill the frame metadata in the AGC and AWB algorithm's prepare()
function. Additional metadata for other algorithms will be addressed
later.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

src/ipa/rkisp1/ipa_context.cpp

@@ -77,6 +77,9 @@ namespace libcamera::ipa::rkisp1 {
  * \var IPASessionConfiguration::sensor
  * \brief Sensor-specific configuration of the IPA
  *
+ * \var IPASessionConfiguration::sensor.defVBlank
+ * \brief The default vblank value of the sensor
+ *
  * \var IPASessionConfiguration::sensor.lineDuration
  * \brief Line duration in microseconds
  *