crypto: algif_rng - zeroize buffer with random data

Due to the change to RNGs to always return zero in success case, the RNG
interface must zeroize the buffer with the length provided by the
caller.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/algif_rng.c b/crypto/algif_rng.c
index 67f612c..a346173 100644
--- a/crypto/algif_rng.c
+++ b/crypto/algif_rng.c
@@ -87,7 +87,7 @@
 		return genlen;
 
 	err = memcpy_to_msg(msg, result, len);
-	memzero_explicit(result, genlen);
+	memzero_explicit(result, len);
 
 	return err ? err : len;
 }