crypto: af_alg - Allow af_af_alg_release_parent to be called on nokey path

commit 6a935170 upstream.

This patch allows af_alg_release_parent to be called even for
nokey sockets.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>