mlx5/mlx5en: Add SQ remap support

Add support to map an SQ to a specific schedule queue using a
special WQE as performance enhancement.

SQ remap operation is handled by a privileged internal queue, IQ,
and the mapping is enabled from one rate to another.

The transition from paced to non-paced should however always go
through FW.

MFC after: 1 week
Sponsored by: NVIDIA Networking