freedreno: Destroy syncobj too when destroying fence

This is a missing part of freedreno EXT_semaphore support,
recently merged as part of series adding EXT_external_objects. This hunk was
actually lost due to a mistake on my side while doing a rebase.

Reviewed-by: Hyunjun Ko <zzoon@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6383>
diff --git a/src/gallium/drivers/freedreno/freedreno_fence.c b/src/gallium/drivers/freedreno/freedreno_fence.c
index 9f0f6ee..29ee662 100644
--- a/src/gallium/drivers/freedreno/freedreno_fence.c
+++ b/src/gallium/drivers/freedreno/freedreno_fence.c
@@ -70,6 +70,8 @@
 {
 	if (fence->fence_fd != -1)
 		close(fence->fence_fd);
+	if (fence->syncobj)
+		drmSyncobjDestroy(fd_device_fd(fence->screen->dev), fence->syncobj);
 	fd_pipe_del(fence->pipe);
 	FREE(fence);
 }