This patch enables software (and phy device) transmit time stamping
for the DaVinci EMAC driver. Tested together with the dp83640 PHY.
Cc: Anant Gole <anantgole@ti.com> Cc: Kevin Hilman <khilman@deeprootsystems.com> Signed-off-by: Richard Cochran <richard.cochran@omicron.at> Signed-off-by: David S. Miller <davem@conan.davemloft.net>