i40evf: remove I40E_FLAG_FDIR_ATR_ENABLED

The flag used by the common code and PF code is I40E_FLAG_FD_ATR_ENABLED,
not *FDIR*. It turns out none of the txrx code actually shared with the
VF driver actually checks the ATR flag. This is made even more obvious
by the typo in the VF header file.

Let's just remove the flag from the VF driver since it's not needed.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>