Bump i40e to 1.2.12 and i40evf to 1.2.6.

Change-ID: I641871da3a9abd396b28eda5744a4d68493c1400
Signed-off-by: Sravanthi Tangeda <sravanthi.tangeda@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>