net/mlx5: Enable single IRQ for PCI Function

Prior to this patch the driver requires two IRQs to function properly,
one required IRQ for control and at least one required IRQ for IO.

This requirement can be relaxed to one as the driver now allows
sharing of IRQs, so control and IO EQs can share the same irq.

This is needed for high scale amount of VFs.

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