net/mlx5e: Refactor rx handler of represetor device

Move the ownership of skb forwarding to network stack to the
tc update_skb handler as different cases will require different
handling of the skb.

While the tc handler will take care of the various cases and
properly handle the handover of the skb to the network stack
and freeing the skb, the main rx handler will be kept clean
from branches and usage of flags.

Signed-off-by: Ariel Levkovich <lariel@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>