i40e: exit ATR mode only when adding TCP/IPv4 filter succeeds

Move ATR exit check after we have sent the TCP/IPv4 filter to the ring
successfully. This avoids an issue where we potentially update the
filter count without actually succeeding in adding the filter. Now, we
only increment the fd_tcp_rule after we've succeeded. Additionally, we
will re-enable ATR mode only after deletion of the filter is actually
posted to the FDIR ring.

Change-ID: If5c1dea422081cc5e2de65618b01b4c3bf6bd586
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-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>