i40e: Move all UDP port notifiers to single function

This patch goes through and combines the notifiers for VXLAN and GENEVE
into a single function for each action.  So there is now one combined
function for getting ports, one for adding the ports, and one for deleting
the ports.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>