We need to set shared_count even if we already have a fence to wait for.

v2: init i to -1 as well
Signed-off-by: NChristian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org
Tested-by: NLyude Paul <lyude@redhat.com>
Reviewed-by: NLyude Paul <lyude@redhat.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180122200003.6665-1-christian.koenig@amd.com