[CRYPTO] api: Split out low-level API

The crypto API is made up of the part facing users such as IPsec and the
low-level part which is used by cryptographic entities such as algorithms.
This patch splits out the latter so that the two APIs are more clearly
delineated.  As a bonus the low-level API can now be modularised if all
algorithms are built as modules.

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

crypto/proc.c

@@ -113,3 +113,8 @@ void __init crypto_init_proc(void)
 	if (proc)
 		proc->proc_fops = &proc_crypto_ops;
 }
+
+void __exit crypto_exit_proc(void)
+{
+	remove_proc_entry("crypto", NULL);
+}