ice: Fix broken link in ice NAPI doc

Current link for NAPI documentation in ice driver doesn't work - it
returns 404. Update the link to the working one.

Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>