alg_key_len is the length in bits of the key, not in bytes.

Best way to fix this is to move alg_len() function from net/xfrm/xfrm_user.c 
to include/net/xfrm.h, and to use it in xfrm_algo_clone()

alg_len() is renamed to xfrm_alg_len() because of its global exposition.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>