devinet: use in_dev_for_each_ifa_rcu in more places

This also replaces spots that used for_primary_ifa().

for_primary_ifa() aborts the loop on the first secondary address seen.

Replace it with either the rcu or rtnl variant of in_dev_for_each_ifa(),
but two places will now also consider secondary addresses too:
inet_addr_onlink() and inet_ifa_byprefix().

I do not understand why they should ignore secondary addresses.

Why would a secondary address not be considered 'on link'?
When matching a prefix, why ignore a matching secondary address?

Other places get converted as well, but gain "->flags & SECONDARY" check.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>