i40e: Persistent LLDP support

This patch adds a function to read NVM module data and uses it to
read current LLDP agent configuration from NVM API version 1.8.

Signed-off-by: Sylwia Wnuczko <sylwia.wnuczko@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>