datapath: Remove vport MAC address configuration.

datapath: Remove vport MAC address configuration.

The ability to retrieve and set MAC addresses on vports is only
necessary for tunnel ports (the addresses for actual devices can be
retrieved through direct Linux mechanisms).  Tunnel ports only used
the information for the purpose of generating path MTU discovery
packets, which has now been removed.  Current userspace code already
reflects these changes, so this drops the functionality from the
kernel.

Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Kyle Mestery <kmestery@cisco.com>