Merge branch 'ipv6-couple-of-fixes-for-rcu-change-to-from'

David Ahern says:

====================
net/ipv6: couple of fixes for rcu change to from

So many details... I am thankful for all the robots running the
permutations and tools.

Two bug fixes from the rcu change to rt->from:
1. missing rcu lock in ip6_negative_advice
2. rcu dereferences in 2 sites
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Signed-off-by: David S. Miller <davem@davemloft.net>