radeonsi/vcn: don't early return if fence isn't prev_fence
What does this MR do and why?
radeonsi/vcn: don't early return if fence isn't prev_fence
Early returning and not waiting for the timeout for the case where fence isn't the last fence caused issues in clients when seeking, so just revert this part.
Fixes: f638ba46 ("radeonsi/vcn: Fix leaking fences in decode")
Closes: #9834 (closed)