[qca-nss-ecm]: deliver network device event to front end

Sometimes front end want to respond to network device event by itself.
So a new callback 'regeneration_needed' is added to front end. This
function will be triggered when generation of connection changed after
network device event.

Change-Id: I163f50508fe70d48f5dd6983cc070d3e10ef242a
Signed-off-by: Xiaoping Fan <xfan@codeaurora.org>
16 files changed