libcamera: control_ids: Generate map of all supported controls

In order to deserialise a ControlList, we will need to lookup ControlId
instances based on their numerical ID. Generate a global map from the
controls definitions to support such a lookup.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Tested-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

include/libcamera/control_ids.h.in

@@ -24,6 +24,8 @@ ${ids}
 
 ${controls}
 
+extern const ControlIdMap controls;
+
 } /* namespace controls */
 
 } /* namespace libcamera */

include/libcamera/controls.h

@@ -111,6 +111,7 @@ private:
 	ControlValue max_;
 };
 
+using ControlIdMap = std::unordered_map<unsigned int, const ControlId *>;
 using ControlInfoMap = std::unordered_map<const ControlId *, ControlRange>;
 
 class ControlList