Supports hardware and software time stamping via the
Linux SO_TIMESTAMPING socket option.

Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: NAtul Gupta <atul.gupta@chelsio.com>
Signed-off-by: NGanesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>