net/mlx5: QPTS and QPDPM register firmware command support

The QPTS register allows changing the priority trust state between pcp and
dscp. Add support to get/set trust state from device. When the port is
in pcp/dscp trust state, packet is routed by hardware to matching priority
based on its pcp/dscp value respectively.

The QPDPM register allow channing the dscp to priority mapping. Add support
to get/set dscp to priority mapping from device.
Note that to change a dscp mapping, the "e" bit of this dscp structure
must be set in the QPDPM firmware command.

Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>