net/mlx5e: Take HW interrupt trigger into a function

mlx5e_trigger_irq posts a NOP to the ICO SQ just to trigger an IRQ and
enter the NAPI poll on the right CPU according to the affinity. Use it
in mlx5e_activate_rq.

Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>