Add an epic_stats_update() function (called once per second). Even though we don't collect any stats in it, we mii_tick() in it! This fix the bug when autonegotiating fullduplex modes.
Add an epic_stats_update() function (called once per second). Even though
we don't collect any stats in it, we mii_tick() in it! This fix the bug
when autonegotiating fullduplex modes.

Also, pause activity before setting TXCON in epic_miibus_statchg(). Though
i've never seen problmes from not doing that, the documentation says we
need to do it.

MFC after:	1 week

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