crypto: rng - Remove old low-level rng interface

Now that all rng implementations have switched over to the new
interface, we can remove the old low-level interface.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/include/crypto/internal/rng.h b/include/crypto/internal/rng.h
index 2c9a865..263f1a5 100644
--- a/include/crypto/internal/rng.h
+++ b/include/crypto/internal/rng.h
@@ -2,6 +2,7 @@
  * RNG: Random Number Generator  algorithms under the crypto API
  *
  * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
+ * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
@@ -16,8 +17,6 @@
 #include <crypto/algapi.h>
 #include <crypto/rng.h>
 
-extern const struct crypto_type crypto_rng_type;
-
 int crypto_register_rng(struct rng_alg *alg);
 void crypto_unregister_rng(struct rng_alg *alg);
 int crypto_register_rngs(struct rng_alg *algs, int count);