Move the setting of flow control because this should be done at a pf level not
a vsi level. Also add a sleep and restart an to fix a bug where Rx would stop
after some stress.

Change-ID: I9a93d8c2ff27c39339eb00bc4ec1225e43900be0
Signed-off-by: NAnjali Singhai Jain <anjali.singhai@intel.com>
Signed-off-by: NJesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: NJim Young <jamesx.m.young@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>