net/mlx5: Change IRQ storage logic from static to dynamic

Store newly created IRQs in the xarray DB instead of a static array,
so we will be able to store only IRQs which are being used.

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