net: sysfs: Fix /sys/class/net/<iface> path for statistics

The Documentation/ABI/testing/sysfs-class-net-statistics documentation
is pointing to the wrong path for the interface. Documentation is
pointing to /sys/class/<iface>, instead of /sys/class/net/<iface>.

Fix it by adding the `net/` directory before the interface.

Fixes: 6044f9700645 ("net: sysfs: document /sys/class/net/statistics/*")
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation: net-sysfs: describe missing statistics

Sync the ABI description with the interface statistics that are currently
available through sysfs.

CC: Jarod Wilson <jarod@redhat.com>
CC: Jonathan Corbet <corbet@lwn.net>
CC: linux-doc@vger.kernel.org
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sysfs: document /sys/class/net/statistics/*

Document the network device statistics counter that are exposed as sysfs
attributes.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>