monitor-transform: Invert the behaviour of transform_point

Previously it transformed a physical CRTC coordinate to a logical desktop
coordinate. But current and future users of the function all require
conversion from logical coordinates to physical coordinates. We would have
had to always invert the transform parameter which is a waste of time when
we can instead just invert the function behaviour.

We also simplify the parameters to show both the point coordinate and the
area dimensions are potentially transformed.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3180>

src/backends/native/meta-cursor-renderer-native.c

@@ -575,8 +575,7 @@ calculate_crtc_cursor_hotspot (MetaCursorSprite     *cursor_sprite,
   width = meta_cursor_sprite_get_width (cursor_sprite);
   height = meta_cursor_sprite_get_height (cursor_sprite);
   meta_monitor_transform_transform_point (transform,
-                                          width, height,
-                                          hot_x, hot_y,
+                                          &width, &height,
                                           &hot_x, &hot_y);
   *hotspot = GRAPHENE_POINT_INIT (hot_x * scale, hot_y * scale);
 }