If reservation_object_get_fences_rcu failed, we'd previously go directly
to the cleanup label, so we'd leave the BO pinned.

While we're at it, remove two amdgpu_bo_unreserve calls in favour of two
new labels.
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NMichel Dänzer <michel.daenzer@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>