net: atm: Add another IS_ENABLED(CONFIG_COMPAT) in atm_dev_ioctl

I removed compat's universal assignment to 0, which allows this if
statement to fall through when compat is passed with a value other
than 0.

Fixes: f9d19a7 ("net: atm: Use IS_ENABLED in atm_dev_ioctl")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/atm/resources.c

@@ -413,7 +413,7 @@ int atm_dev_ioctl(unsigned int cmd, void __user *arg, int compat)
 		}
 		/* fall through */
 	default:
-		if (compat) {
+		if (IS_ENABLED(CONFIG_COMPAT) && compat) {
 #ifdef CONFIG_COMPAT
 			if (!dev->ops->compat_ioctl) {
 				error = -EINVAL;