[addon] remove not needed header comment in CScreenSaver

[AlwinEsch]

The comment says 'Things that MUST be supplied by the child classes', but there
are no childs, is everything inside him.

[AlwinEsch]

jenkins build this please and merge

[akva2]

childs refer to instances in the context. so it's not wrong as such, just imprecise.

[AlwinEsch]

For me the text was not understandable, to use as calls for screensaver is it clear that the rest of kodi must call them.
And for calls on add-on is it only:

  void Start();
  void Render();
  void GetInfo(SCR_INFO* pInfo);

The GetInfo becomes also removed in future, was never used in Kodi and add-ons.
EDIT: GetInfo is from me from the past with the idea to have it like PVR and to allow add from them.

[akva2]

Not disagreeing or objecting to anything, just providing the information.

[AlwinEsch]

jenkins build this please