Move the ioctl-based VLAN implementation to a separate file to avoid
need for conditional blocks within vlan_ioctl.c. This removes the
internal CONFIG_VLAN_NETLINK define, i.e., this is now used only in
build configuration (.config) to select whether to include the
vlan_util.c (netlink) or vlan_ioctl.c (ioctl) implementation of the
functions.
Signed-off-by: Jouni Malinen <j@w1.fi>
