mlx5e_rep: push cls_flower setup_tc processing into a separate function

Let mlx5e_rep_setup_tc (former mlx5e_rep_ndo_setup_tc) be a splitter for
specific setup_tc types and push out cls_flower specific code into
a separate function.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>