drm/xe/sync: Fix user fence leak on alloc failure

When dma_fence_chain_alloc() fails, properly release the user fence
reference to prevent a memory leak.

Fixes: 0995c2f ("drm/xe: Enforce correct user fence signaling order using")
Cc: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260219233516.2938172-6-shuicheng.lin@intel.com
(cherry picked from commit a5d5634)
Cc: stable@vger.kernel.org
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Author: ShuichengLin

drivers/gpu/drm/xe/xe_sync.c

@@ -206,8 +206,10 @@ int xe_sync_entry_parse(struct xe_device *xe, struct xe_file *xef,
 			if (XE_IOCTL_DBG(xe, IS_ERR(sync->ufence)))
 				return PTR_ERR(sync->ufence);
 			sync->ufence_chain_fence = dma_fence_chain_alloc();
-			if (!sync->ufence_chain_fence)
-				return -ENOMEM;
+			if (!sync->ufence_chain_fence) {
+				err = -ENOMEM;
+				goto free_sync;
+			}
 			sync->ufence_syncobj = ufence_syncobj;
 		}