crypto: af_alg - Allow arbitrarily long algorithm names

This patch removes the hard-coded 64-byte limit on the length
of the algorithm name through bind(2).  The address length can
now exceed that.  The user-space structure remains unchanged.
In order to use a longer name simply extend the salg_name array
beyond its defined 64 bytes length.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>