During iteration process one of the proposed mechanism for not
breaking existing userspace was to report writeback connectors as
disconnected, however the final version used
DRM_CLIENT_CAP_WRITEBACK_CONNECTORS for that purpose.

Change-Id: I2319d099f7669094c8530f1521abdbca08e76486
Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@arm.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patchwork.freedesktop.org/patch/238399/