i40e: track filter type statistics when deleting invalid filters

i40e: track filter type statistics when deleting invalid filters

When hardware has trouble with a particular filter, we delete it from
the list. Unfortunately, we did not properly update the per-filter
statistic when doing so.

Create a helper function to handle this, and properly reduce the
necessary counter so that it tracks the number of active filters
properly.

Signed-off-by: Jacob Keller <[email protected]>
Tested-by: Andrew Bowers <[email protected]>
Signed-off-by: Jeff Kirsher <[email protected]>