common/mlx5: share DevX queue pair operations

common/mlx5: share DevX queue pair operations

Currently drivers using QP (vDPA, crypto and compress, regex soon)
manage their memory, creation, modification and destruction of the QP,
in almost identical code.
Move QP memory management, creation and destruction to common.
Add common function to change QP state to RTS.
Add user_index attribute to QP creation.
It's for better code maintenance and reuse.

Signed-off-by: Raja Zidane <rzidane@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>