drm/xe: Use dma_fence_chain_free in chain fence unused as a sync

drm/xe: Use dma_fence_chain_free in chain fence unused as a sync

A chain fence is uninitialized if not installed in a drm sync obj. Thus
if xe_sync_entry_cleanup is called and sync->chain_fence is non-NULL the
proper cleanup is dma_fence_chain_free rather than a dma-fence put.

Reported-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2411
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2261
Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240727012216.2118276-1-matthew.brost@intel.com