i40e: Enable Geneve offload for FW API ver > 1.4 for XL710/X710 devices

This patch makes sure we check the GENEVE offload capable flag before
we attempt offload.
It also enables the Capability for XL710/X710 devices with FW API
version higher than 1.4

Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>