This function uses the global nexthop policy only to then bounce all
arguments except for NHA_ID. Instead, just create a new policy that
only includes the one allowed attribute.
Signed-off-by: NPetr Machata <petrm@nvidia.com>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>