ipa: rkisp1: agc: Introduce HW revision in IPAContext

The ISP can use 25 or 81 cells depending on its revision. Remove the
cached value in IPARkISP1 and use IPASessionConfiguration to store it
and pass it to AGC later.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/ipa/rkisp1/ipa_context.cpp

@@ -55,4 +55,12 @@ namespace libcamera::ipa::rkisp1 {
  * are run. This needs to be turned into real per-frame data storage.
  */
 
+/**
+ * \var IPASessionConfiguration::hw
+ * \brief RkISP1-specific hardware information
+ *
+ * \var IPASessionConfiguration::hw.revision
+ * \brief Hardware revision of the ISP
+ */
+
 } /* namespace libcamera::ipa::rkisp1 */