Merge branch 'alx_stats'

Sabrina Dubroca says:

====================
alx: add statistics

Currently, the alx driver doesn't support statistics [1,2]. The
original alx driver [3] that Johannes Berg modified provided
statistics. This patch is an adaptation of the statistics code from
the original driver to the alx driver included in the kernel.

v4:
 - modified the assignements of hw stats to netstats (Ben Hutchings)
 - added comments to describe the stats fields (copied from atlx)

v3:
 - renamed __alx_update_hw_stats to alx_update_hw_stats (Stephen Hemminger)

v2:
 - use u64 instead of unsigned long  (Ben Hutchings)
 - implement ndo_get_stats64 instead of ndo_get_stats (Ben Hutchings)
 - use EINVAL instead of ENOTSUPP  (Ben Hutchings)
 - add BUILD_BUG_ON to check the size of the stats (Johannes Berg, Ben
   Hutchings)
 - add a comment regarding persistence of the stats (Stephen Hemminger)
 - align assignments in __alx_update_hw_stats

[1] https://bugzilla.kernel.org/show_bug.cgi?id=63401
[2] http://www.spinics.net/lists/netdev/msg245544.html
[3] https://github.com/mcgrof/alx
====================

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