net: sockev: filtering non INET socket events

Too many socket events are generated by netlink socket. Filtering out
unwanted socket events.

Change-Id: I3a4d7e14843cf72d6af2d948113b27928ed01adb
Acked-by: Krishnan Ramachandran <kramacha@qti.qualcomm.com>
Signed-off-by: Harout Hedeshian <harouth@codeaurora.org>