i40e: fix scheduling in set_rx_mode

i40e: fix scheduling in set_rx_mode

Add service task schedule to set_rx_mode.
In some cases there are error messages printed out in PTP application
(ptp4l):

ptp4l[13848.762]: port 1 (ens2f3np3): received SYNC without timestamp
ptp4l[13848.825]: port 1 (ens2f3np3): received SYNC without timestamp
ptp4l[13848.887]: port 1 (ens2f3np3): received SYNC without timestamp

This happens when service task would not run immediately after
set_rx_mode, and we need it for setup tasks. This service task checks, if
PTP RX packets are hung in firmware, and propagate correct settings such
as multicast address for IEEE 1588 Precision Time Protocol.
RX timestamping depends on some of these filters set. Bug happens only
with high PTP packets frequency incoming, and not every run since
sometimes service task is being ran from a different place immediately
after starting ptp4l.

Fixes: 0e4425ed641f ("i40e: fix: do not sleep in netdev_ops")
Reviewed-by: Grzegorz Nitka <grzegorz.nitka@intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Przemyslaw Korba <przemyslaw.korba@intel.com>
Tested-by: Rinitha S <sx.rinitha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>