i40e: Helper routine for Rx/Tx queue enable/disable wait

Introduce helper routines that would wait for the Rx/Tx queue
to reach the enable or disable state as requested.

Change-ID: I518d9d0e2afef3f45107af3b46e9af402ff587c3
Signed-off-by: Neerav Parikh <neerav.parikh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>