LANConf: Minor Fixes
LANConf: Minor Fixes

1) Get the interface mode of the system if it is not given
    so that we can set the same interface mode as it was before.
2) Removed the unnecessary condition of getting the VLAN.

Resolves openbmc/openbmc#2738

Change-Id: I1658fbf78627e7cc1c7e1e5875964ed30c58d6dc
Signed-off-by: Ratan Gupta <a42a43504c26cfe5294e3d72712325cd74a43440@in.ibm.com>

openbmc/phosphor-host-ipmid,openbmc/phosphor-host-ipmid,openbmc/phosphor-host-ipmid