net: Align ip_multipath_l3_keys and ip6_multipath_l3_keys

net: Align ip_multipath_l3_keys and ip6_multipath_l3_keys

Symmetry is good and allows easy comparison that ipv4 and ipv6 are
doing the same thing. To that end, change ip_multipath_l3_keys to
set addresses at the end after the icmp compares, and move the
initialization of ipv6 flow keys to rt6_multipath_hash.

Signed-off-by: David Ahern <[email protected]>
Reviewed-by: Ido Schimmel <[email protected]>
Reviewed-by: Nikolay Aleksandrov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>