mlx4: Don't bother using skb_tx_hash in mlx4_en_select_queue

The code in the fallback path has supported XDP in conjunction with the Tx
traffic classification for TCs for over a year now. So instead of just
calling skb_tx_hash for every packet we are better off using the fallback
since that will record the Tx queue to the socket and then that can be used
instead of having to recompute the hash every time.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>