i40evf: main driver core

This is the driver for the Intel(R) XL710 X710 Virtual Function.

This patch contains the main driver entry points, but does not include
transmit and receive or ethtool functionality, which are presented as
separate patches in this series.
Signed-off-by: NMitch Williams <mitch.a.williams@intel.com>
Signed-off-by: NGreg Rose <gregory.v.rose@intel.com>
Tested-by: NSibai Li <sibai.li@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>