ipv4: Set nexthop flags in a more consistent way

Be more consistent about the way in which the nexthop flags are set and
set them in one go.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20201110102553.1924232-1-idosch@idosch.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv4/fib_semantics.c

@@ -1641,11 +1641,8 @@ int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
 		break;
 	}
 
-	*flags |= (nhc->nhc_flags & RTNH_F_ONLINK);
-	if (nhc->nhc_flags & RTNH_F_OFFLOAD)
-		*flags |= RTNH_F_OFFLOAD;
-	if (nhc->nhc_flags & RTNH_F_TRAP)
-		*flags |= RTNH_F_TRAP;
+	*flags |= (nhc->nhc_flags &
+		   (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
 
 	if (!skip_oif && nhc->nhc_dev &&
 	    nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))