staging: fsl-dpaa2/eth: Add support for hardware timestamping

Hardware timestamping is supported both on Rx and Tx paths.
On Rx, timestamping is enabled for all frames. On Tx, we
only instruct the hardware to timestamp the frames marked
accordingly by the stack.

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>