i40e: properly show packet split status in debugfs

Get rid of the unused hsplit field in the ring struct and use the
existing macro to detect packet split enablement. This allows debugfs
dumps of the VSI to properly show which Rx routine is in use.

Change-ID: Ic4e9589e6a788ab196ed0850703f704e30c03781
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>