i40evf: handle many MAC filters correctly

i40evf: handle many MAC filters correctly

When a lot (many hundreds) of MAC or VLAN filters are added at one time,
we can overflow the Admin Queue buffer size with all the requests.
Unfortunately, the driver would then calculate the message size
incorrectly, causing it to be rejected by the PF. Furthermore, there was
no mechanism to trigger another request to allow for configuring the
rest of the filters that didn't fit into the first request.

To fix this, recalculate the correct buffer size when we detect the
overflow condition instead of just assuming the max buffer size. Also,
don't clear the request bit in adapter->aq_required when we have an
overflow, so that the rest of the filters can be processed later.

Change-ID: Idd7cbbc5af31315e0dcb1b10e6a02ad9817ce65c
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>