drm/etnaviv: fix bogus fence complete check in timeout handler

The GPU hardware fences and the job out-fences are on different timelines
so it's wrong to compare them. Fix this by only looking at the out-fence.

Cc: <stable@vger.kernel.org>
Fixes: 2c83a726 (drm/etnaviv: bring back progress check in job
                     timeout handler)
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>