octeontx2-af: Implement represetee state notification

commit 2b7203ced7520d24e715ff84a252264a6301d895 from
git@git.assembla.com:cavium/WindRiver.linux.git

Implementing a mechanism to notify the representor port whenever
its respective representee (or represented port) comes up or goes
down.

Signed-off-by: Harman Kalra <hkalra@marvell.com>
Change-Id: I1fd335c1e7da573646f60d0bb84ddb113023ef0a
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/120598
Tested-by: sa_ip-sw-jenkins <sa_ip-sw-jenkins@marvell.com>
Reviewed-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>