ptp: tilegx: convert to the 64 bit get/set time methods.

This driver is 64 bit only, and so this driver and device are ready
for 2038.  This patch changes the driver to the new PHC and also
carries the timespec64 parameter on out to the gxio_mpipe_get-
set_timestamp functions, making explicit the fact that the tv_sec
field is 64 bits wide.

Not even compile tested.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: Chris Metcalf <cmetcalf@ezchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>