i40e: do a proper reset when disabling a VF

The VF disable code was just whanging on the reset bit without properly
cleaning up the VF, which would leave the VF in an indeterminate state
from which it could not recover. Fix this by notifying the VF and then
by calling the normal VF reset routine.

Change-ID: I862b9dfa919368773cbdc212b805b520db2f7430
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Jim Young <james.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>