freerdp-extension-xpunlimited: Remove the recipe as it is uncompatible

The 1.0 version of FreeRDP has change a lot and made the extension to
fail; as this extension has some limit usage (due some legal
interpretations) we stoped to support it upstream and in O.S. Systems.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>