i40evf: Clean-up flags for promisc mode to avoid high polling rate

If you enabled and disabled promiscuous mode on a VF you could easily put
it into a state where it would start firing interrupts on all queues at a
rate of 50+ interrupts per second even though there was no traffic present.
The issue seems to have been a stray admin queue feature flag set that was
leaving us in a high polling rate for the adminq task.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>