vsock: remove ratelimit unknown ioctl message

When exercising the kernel with stress-ng with some ioctl tests the
"Unknown ioctl" error message is spamming the kernel log at a high
rate. Remove this message.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/vmw_vsock/af_vsock.c

@@ -2072,7 +2072,6 @@ static long vsock_dev_do_ioctl(struct file *filp,
 		break;
 
 	default:
-		pr_err("Unknown ioctl %d\n", cmd);
 		retval = -EINVAL;
 	}