transport->stream_enqueue may call copy_to_user so it should
not be called inside a prepare_to_wait. Narrow the scope of
the prepare_to_wait to avoid the bad call. This also applies
to vsock_stream_recvmsg as well.
Reported-by: Vinson Lee <vlee@freedesktop.org> Tested-by: Vinson Lee <vlee@freedesktop.org> Signed-off-by: Laura Abbott <labbott@fedoraproject.org> Signed-off-by: David S. Miller <davem@davemloft.net>