i40e: better error messages for NVM update issues

Add more detail to the NVM update error messages so folks
have a better chance at diagnosing issues without having to
resort to heroic measures to reproduce an issue.

Change-ID: I270d1a9c903baceaef0bebcc55d29108ac08b0bd
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Jim Young <jamesx.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>