ipa: camera_sensor_helper: Make factory createInstance() function const

The CameraSensorHelperFactory::createInstance() function has no need to
modify the factory instance. Make it const.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Xavier Roumegue <xavier.roumegue@oss.nxp.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

src/ipa/libipa/camera_sensor_helper.cpp

@@ -254,10 +254,10 @@ CameraSensorHelperFactory::CameraSensorHelperFactory(const std::string name)
  */
 std::unique_ptr<CameraSensorHelper> CameraSensorHelperFactory::create(const std::string &name)
 {
-	std::vector<CameraSensorHelperFactory *> &factories =
+	const std::vector<CameraSensorHelperFactory *> &factories =
 		CameraSensorHelperFactory::factories();
 
-	for (CameraSensorHelperFactory *factory : factories) {
+	for (const CameraSensorHelperFactory *factory : factories) {
 		if (name != factory->name_)
 			continue;
 
@@ -299,7 +299,7 @@ std::vector<CameraSensorHelperFactory *> &CameraSensorHelperFactory::factories()
 }
 
 /**
- * \fn CameraSensorHelperFactory::createInstance()
+ * \fn CameraSensorHelperFactory::createInstance() const
  * \brief Create an instance of the CameraSensorHelper corresponding to the
  * factory
  *

src/ipa/libipa/camera_sensor_helper.h

@@ -70,7 +70,7 @@ public:
 	static std::vector<CameraSensorHelperFactory *> &factories();
 
 protected:
-	virtual CameraSensorHelper *createInstance() = 0;
+	virtual CameraSensorHelper *createInstance() const = 0;
 
 private:
 	LIBCAMERA_DISABLE_COPY_AND_MOVE(CameraSensorHelperFactory)
@@ -85,7 +85,7 @@ public: 							\
 	helper##Factory() : CameraSensorHelperFactory(name) {}	\
 								\
 private:							\
-	CameraSensorHelper *createInstance()			\
+	CameraSensorHelper *createInstance() const		\
 	{							\
 		return new helper();				\
 	}							\