[S390] use kzfree()

Use kzfree() instead of memset() + kfree().

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/crypto/prng.c

@@ -201,8 +201,7 @@ out_free:
 static void __exit prng_exit(void)
 {
 	/* wipe me */
-	memset(p->buf, 0, prng_chunk_size);
-	kfree(p->buf);
+	kzfree(p->buf);
 	kfree(p);
 
 	misc_deregister(&prng_dev);

drivers/s390/crypto/zcrypt_pcixcc.c

@@ -781,8 +781,7 @@ static long zcrypt_pcixcc_send_cprb(struct zcrypt_device *zdev,
 		/* Signal pending. */
 		ap_cancel_message(zdev->ap_dev, &ap_msg);
 out_free:
-	memset(ap_msg.message, 0x0, ap_msg.length);
-	kfree(ap_msg.message);
+	kzfree(ap_msg.message);
 	return rc;
 }