net/mlx5: Introduce API for request and release IRQs

Introduce new API that will allow IRQs users to hold a pointer to
mlx5_irq.
In the end of this series, IRQs will be allocated on demand. Hence,
this will allow us to properly manage and use IRQs.

Signed-off-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>