Restore igb(4) code dropped during iflib conversion

• restore newer code for vf, i350, i210, i211
• restore dmac init code for i354 and i350
• restore WUC/WUFC update
• check for igb mac type before attempting trying to assert a media changed event.
• handle link events for igb(4) and em(4) devices differently and appropriately for their respective model types.

Submitted by: Matt Macy <mmacy@mattmacy.io>
Sponsored by: Limelight Networks