crypto: api - Rebirth of crypto_alloc_tfm

This patch reintroduces a completely revamped crypto_alloc_tfm.
The biggest change is that we now take two crypto_type objects
when allocating a tfm, a frontend and a backend.  In fact this
simply formalises what we've been doing behind the API's back.

For example, as it stands crypto_alloc_ahash may use an
actual ahash algorithm or a crypto_hash algorithm.  Putting
this in the API allows us to do this much more cleanly.

The existing types will be converted across gradually.

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

include/linux/crypto.h

@@ -546,7 +546,9 @@ struct crypto_attr_u32 {
  * Transform user interface.
  */
  
-struct crypto_tfm *crypto_alloc_tfm(const char *alg_name, u32 tfm_flags);
+struct crypto_tfm *crypto_alloc_tfm(const char *alg_name,
+				    const struct crypto_type *frontend,
+				    u32 type, u32 mask);
 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask);
 void crypto_free_tfm(struct crypto_tfm *tfm);