net/mlx5e: Avoid doing a cleanup call if the profile doesn't have it

The error flow of mlx5e_create_netdev calls the cleanup call
of the given profile without checking if it exists, fix that.

Currently the VF reps don't register that callback and we crash
if getting into error -- can be reproduced by the user doing ctrl^C
while attempting to change the sriov mode from legacy to switchdev.

Fixes: 26e59d8077a3 '(net/mlx5e: Implement mlx5e interface attach/detach callbacks')
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reported-by: Sabrina Dubroca <sdubroca@redhat.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

@@ -4241,7 +4241,8 @@ struct net_device *mlx5e_create_netdev(struct mlx5_core_dev *mdev,
 	return netdev;
 
 err_cleanup_nic:
-	profile->cleanup(priv);
+	if (profile->cleanup)
+		profile->cleanup(priv);
 	free_netdev(netdev);
 
 	return NULL;