net/mlx5: support flow tag and packet header miniCQEs

net/mlx5: support flow tag and packet header miniCQEs

CQE compression allows us to save the PCI bandwidth and improve
the performance by compressing several CQEs together to a miniCQE.
But the miniCQE size is only 8 bytes and this limits the ability
to successfully keep the compression session in case of various
traffic patterns.

The current miniCQE format only keeps the compression session alive
in case of uniform traffic with the Hash RSS as the only difference.
There are requests to keep the compression session in case of tagged
traffic by RTE Flow Mark Id and mixed UDP/TCP and IPv4/IPv6 traffic.
Add 2 new miniCQE formats in order to achieve the best performance
for these traffic patterns: Flow Tag and Packet Header miniCQEs.

The existing rxq_cqe_comp_en devarg is modified to specify the
desired miniCQE format. Specifying 2 selects Flow Tag format
for better compression rate in case of RTE Flow Mark traffic.
Specifying 3 selects Checksum format (existing format for MPRQ).
Specifying 4 selects L3/L4 Header format for better compression
rate in case of mixed TCP/UDP and IPv4/IPv6 traffic.

Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>