virtio_net: implements ethtool_ops.get_drvinfo
virtio_net: implements ethtool_ops.get_drvinfo

I often use "ethtool -i" command to check what driver controls the
ehternet device.  But because current virtio_net driver doesn't
support "ethtool -i", it becomes the following:

        # ethtool -i eth3
        Cannot get driver information: Operation not supported

This patch simply adds the "ethtool -i" support. The following is the
result when using the virtio_net driver with my patch applied to.

        # ethtool -i eth3
        driver: virtio_net
        version: N/A
        firmware-version: N/A
        bus-info: virtio0

Personally, "-i" is one of the most frequently-used option, and most
network drivers support "ethtool -i", so I think virtio_net also
should do.

Signed-off-by: Taku Izumi <23ca3fc138fbd3784aec73bbc7a412bdd1fcadfc@jp.fujitsu.com>
Signed-off-by: Rusty Russell <df9728c9e5104131c08c7adb03af425394842596@rustcorp.com.au> (use ARRAY_SIZE)
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas