fix return value for syncobj wait

otherwise -ETIME is missed.

Signed-off-by: Chunming Zhou <david1.zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>

xf86drm.c

@@ -4278,7 +4278,7 @@ int drmSyncobjWait(int fd, uint32_t *handles, unsigned num_handles,
 
     ret = drmIoctl(fd, DRM_IOCTL_SYNCOBJ_WAIT, &args);
     if (ret < 0)
-        return ret;
+        return -errno;
 
     if (first_signaled)
         *first_signaled = args.first_signaled;