cxgb4: time stamping interface for PTP
Supports hardware and software time stamping via the Linux SO_TIMESTAMPING socket option. Cc: Richard Cochran <richardcochran@gmail.com> Signed-off-by: Atul Gupta <atul.gupta@chelsio.com> Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com> Signed-off-by: David S. Miller <davem@davemloft.net>