mlxsw: spectrum_router: Don't check state when refreshing offload indication

Previous patch removed the reliance on the counter in the FIB info to
set the offload indication, so we no longer need to keep an offload
state on each FIB entry and can just set or unset the RTNH_F_OFFLOAD
flag in each nexthop.

This is also necessary because we're going to need to refresh the
offload indication whenever the nexthop group associated with the FIB
entry is refreshed. Current check would prevent us from marking a newly
resolved nexthop as offloaded if the FIB entry is already marked as
offloaded.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Tested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>