net/mlx5: Extend mlx5_irq_request to request IRQ from the kernel

Extend mlx5_irq_request so that IRQs will be requested upon EQ creation,
and not on driver boot.

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