libcamera: transform: Make the transformFromOrientation() function static

Now that the transformFromOrientation() function isn't used outside of
transform.cpp, make it static to remove it from the public API.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

src/libcamera/transform.cpp

@@ -301,6 +301,8 @@ Transform transformFromRotation(int angle, bool *success)
 	return Transform::Identity;
 }
 
+namespace {
+
 /**
  * \brief Return the transform representing \a orientation
  * \param[in] orientation The orientation to convert
@@ -330,6 +332,8 @@ Transform transformFromOrientation(const Orientation &orientation)
 	return Transform::Identity;
 }
 
+} /* namespace */
+
 /**
  * \brief Return the Transform that applied to \a o2 gives \a o1
  * \param o1 The Orientation to obtain