Don't handle the ipv6 routing advertisement message

In ipv6 network where ipv6 router is there which keeps advertising
the router prefix, as part of handling this message BMC keeps adding the
new IP address on the interface which is leading to refresh the
network objects periodically.
This fix stops accepting the router advertisement messaage.

Resolves openbmc/openbmc#2739

Change-Id: I0a4068b5419133a25a2ea3f769f730e73860da50
Signed-off-by: Ratan Gupta <ratagupt@in.ibm.com>
3 files changed