Merge branch 'mpls-cleanups'

Benjamin Poirier says:

====================
net: mpls: Cleanup nexthop iterator macros

The mpls macros for_nexthops and change_nexthops were probably copied
from decnet or ipv4 but they grew a superfluous variable and lost a
beneficial "const".
====================

Signed-off-by: David S. Miller <davem@davemloft.net>