A fence id of zero is expected to be invalid, and is not removed from
the fence_idr table.  If userspace is requesting to specify the fence
id with the FENCE_SN_IN flag, we need to reject a zero fence id value.

Fixes: 17154add ("drm/msm: Add MSM_SUBMIT_FENCE_SN_IN")
Signed-off-by: Rob Clark <robdclark@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/549180/