crypto: rng - Free default RNG on module exit

When the rng module is removed the default RNG will be leaked.
Call crypto_del_default_rng to free it if possible.

Fixes: 7cecadb7cc ("crypto: rng - Do not free default RNG when it becomes unused")
Signed-off-by: Herbert Xu <[email protected]>

crypto/rng.c

@@ -230,5 +230,16 @@ void crypto_unregister_rngs(struct rng_alg *algs, int count)
 }
 EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
 
+static void __exit rng_exit(void)
+{
+	int err;
+
+	err = crypto_del_default_rng();
+	if (err)
+		pr_err("Failed delete default RNG: %d\n", err);
+}
+
+module_exit(rng_exit);
+
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Random Number Generator");