tipc: add media set to new netlink api

tipc: add media set to new netlink api

Add TIPC_NL_MEDIA_SET command to the new tipc netlink API.

This command can set one or more link properties for a particular
media.

Netlink logical layout of bearer set message:
-> media
    -> name
    -> link properties
        [ -> tolerance ]
        [ -> priority ]
        [ -> window ]

Signed-off-by: Richard Alpe <[email protected]>
Reviewed-by: Erik Hugne <[email protected]>
Reviewed-by: Jon Maloy <[email protected]>
Acked-by: Ying Xue <[email protected]>
Signed-off-by: David S. Miller <[email protected]>