bridge: Pass interface's configuration to datapath.

bridge: Pass interface's configuration to datapath.

This commit adds functionality to pass value of 'other_config' column
of 'Interface' table to datapath.

This may be used to pass not directly connected with netdev options and
configure behaviour of the datapath for different ports.
For example: pinning of rx queues to polling threads in dpif-netdev.

Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Acked-by: Daniele Di Proietto <diproiettod@vmware.com>