net: ionic: fix error check for vlan flags in ionic_set_nic_features()

The prototype of input features of ionic_set_nic_features() is
netdev_features_t, but the vlan_flags is using the private
definition of ionic drivers. It should use the variable
ctx.cmd.lif_setattr.features, rather than features to check
the vlan flags. So fixes it.

Fixes: beead698 ("ionic: Add the basic NDO callbacks for netdev support")
Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Acked-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>