[PATCH V5] net/mlx5: support ESP SPI match and RSS hash

[Matan Azrad]

From: Raja Zidane
> In packets with ESP header, The Inner IP will be encrypted, and its fields
> cannot be used for RSS hashing. So, ESP packets can be hashed only by the
> outer IP layer.
> So, when using RSS on ESP packets, hashing may not be efficient, because
> the fields used by the hash functions are only the Outer IPs, causing all traffic
> belonging to all tunnels between a given pair of GWs to land on one core.
> Adding the SPI hash field can extend the spreading of IPSec packets.
> 
> support matching on ESP SPI.
> Support RSS on ESP header by hashing SPI field.
> 
> Signed-off-by: Raja Zidane <rzidane at nvidia.com>
Acked-by: Matan Azrad <matan at nvidia.com>