i40e/i40evf: Add stats to track FD ATR and SB dynamic enable state

Since the driver can dynamically enable/disable FD ATR and SB features,
these stats help keep track of the current state and along with
fd_flush count provide a means to debug what could be going on
with the flow director filters. This will take away the need for
being verbose in our debug logs with respect to FD.

Change-ID: I29224f750fe6602391043655d18996570720377d
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Tested-by: Jim Young <james.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>