crypto: api - remove another reference to blkcipher

Update a comment to refer to crypto_alloc_skcipher() rather than
crypto_alloc_blkcipher() (the latter having been removed).
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/api.c

@@ -516,7 +516,7 @@ EXPORT_SYMBOL_GPL(crypto_find_alg);
  *
  *	The returned transform is of a non-determinate type.  Most people
  *	should use one of the more specific allocation functions such as
- *	crypto_alloc_blkcipher.
+ *	crypto_alloc_skcipher().
  *
  *	In case of error the return value is an error pointer.
  */