Merge branch 'net-ethtool-Introduce-link_ksettings-API-for-virtual-network-devices'

Cris Forno says:

====================
net/ethtool: Introduce link_ksettings API for virtual network devices

This series provides an API for drivers of virtual network devices that
allows users to alter initial device speed and duplex settings to reflect
the actual capabilities of underlying hardware. The changes made include
a helper function ethtool_virtdev_set_link_ksettings, which is used to
retrieve alterable link settings. In addition, there is a new ethtool
function defined to validate those settings. These changes resolve code
duplication for existing virtual network drivers that have already
implemented this behavior.  In the case of the ibmveth driver, this API is
used to provide this capability for the first time.

---
v7:  - removed ethtool_validate_cmd function pointer parameter from
      ethtool_virtdev_set_link_ksettings since none of the virtual drivers
      pass in a custom validate function as suggested by Michal Kubecek.

v6:  - removed netvsc_validate_ethtool_ss_cmd(). netvsc_drv now uses
     ethtool_virtdev_validate_cmd() instead as suggested by Michal Kubecek
     and approved by Haiyang Zhang.

     - matched handler argument name of ethtool_virtdev_set_link_ksettings
     in declaration and definition as suggested by Michal Kubecek.

     - shortened validate variable assignment in
     ethtool_virtdev_set_link_ksettings as suggested by Michal Kubecek.

v5:  - virtdev_validate_link_ksettings is taken out of the ethtool global
     structure and is instead added as an argument to
     ethtool_virtdev_set_link_ksettings as suggested by Jakub Kicinski.

v4:  - Cleaned up return statement in ethtool_virtdev_validate_cmd based
     off of Michal Kubecek's and Thomas Falcon's suggestion.

     - If the netvsc driver is using the VF device in order to get
     accelerated networking, the real speed and duplex is reported by using
     the VF device as suggested by Stephen Hemminger.

     - The speed and duplex variables are now passed by value rather than
     passed by pointer as suggested by Willem de Bruijin and Michal
     Kubecek.

     - Removed ethtool_virtdev_get_link_ksettings since it was too simple
     to warrant a helper function.

v3:  - Factored out duplicated code to core/ethtool to provide API to
     virtual drivers

v2:  - Updated default driver speed/duplex settings to avoid breaking
     existing setups
====================

Signed-off-by: David S. Miller <davem@davemloft.net>