[PATCH] at91_ether: late collistions are counted twice (resubmit)

According to the at91rm9200 datasheet, table 36-6, late collisions
(AT91_EMAC_LCOL) are already counted in the collision register (in scol, mcol or
ecol , depending on the type of error).

So don't count them twice in stats.collisions.

Signed-off-by: Marc Pignat <redacted>
Signed-off-by: Andrew Victor <redacted>