WifiWatchdog: handle exception from ArpPeer

Sometimes IllegalArgumantException can happen in constructor of ArpPeer
class when IPv6 address is provided. This causes crash of systemserver.

Fixing it by adding appropriate exception handler

Change-Id: I4bb7bbca790745a1bf56ece96dd91b84b1f70cad
Signed-off-by: Andrii Beregovenko <a.beregovenko@ti.com>
Signed-off-by: Vishal Mahaveer <vishalm@ti.com>