i40e: Fix add TC filter for IPv6

Fix insufficient distinction between IPv4 and IPv6 addresses
when creating a filter.
IPv4 and IPv6 are kept in the same memory area. If IPv6 is added,
then it's caught by IPv4 check, which leads to err -95.

Fixes: 2f4b411a

 ("i40e: Enable cloud filters via tc-flower")
Signed-off-by: Grzegorz Szczurek <grzegorzx.szczurek@intel.com>
Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
Reviewed-by: Jaroslaw Gawin <jaroslawx.gawin@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>