iavf: schedule a request immediately after add/delete vlan

When the iavf driver wants to reconfigure the VLAN filters
(iavf_add_vlan, iavf_del_vlan), it sets a flag in
aq_required:
  adapter->aq_required |= IAVF_FLAG_AQ_ADD_VLAN_FILTER;
or:
  adapter->aq_required |= IAVF_FLAG_AQ_DEL_VLAN_FILTER;

This is later processed by the watchdog_task, but it runs periodically
every 2 seconds, so it can be a long time before it processes the request.

In the worst case, the interface is unable to receive traffic for more
than 2 seconds for no objective reason.

Fixes: 5eae00c5 ("i40evf: main driver core")
Signed-off-by: Petr Oros <poros@redhat.com>
Co-developed-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Co-developed-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Reviewed-by: Ahmed Zaki <ahmed.zaki@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>