Verify the pipe_fd_type to be of PIPE_FD_TYPE_NATIVE_SYNC.
Fixes: d1a1c21e76 "virgl: native fence fd support"
Suggested-by: Eric Engestrom <eric.engestrom@intel.com>
Signed-off-by: Robert Foss <robert.foss@collabora.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>