datapath: Slim down the vport interface.

datapath: Slim down the vport interface.

Many of the function in vport.c are simply pass throughs to their
underlying vport implementation and, of these, many are used only
for bridge compatibility code.  This allows users of these functions
to directly call through the ops structure, reducing boilerplate code
and keeping more of the compatibility code together.

Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>