i40e: rename index to port to avoid confusion

i40e: rename index to port to avoid confusion

The .index field of i40e_udp_port_config represents the udp port number.
Rename this variable to port so that it is more obvious.

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>
Orabug: 26785018
(cherry picked from commit 27826fd5d357d38b5cf834f9adcc70e6c2254d69)
Signed-off-by: Jack Vogel <jack.vogel@oracle.com>
Reviewed-by: Kyle Fortin <kyle.fortin@oracle.com>