drm/ttm: fix error handling in ttm_buffer_object_transfer

commit 97e000ac upstream.

Unlocking the resv object was missing in the error path, additionally to
that we should move over the resource only after the fence slot was
reserved.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Fixes: c8d4c18b ("dma-buf/drivers: make reserving a shared slot mandatory v4")
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20250616130726.22863-3-christian.koenig@amd.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>