staging: vchiq: Get rid of VCHIQ_SERVICE_OPENEND callback reason

Nobody uses it and it's routinely discarded in vchi.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20200527115400.31391-11-nsaenzjulienne@suse.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>