qede: Add driver support for PTP

This patch adds the driver support for,
  - Registering the ptp clock functionality with the OS.
  - Timestamping the Rx/Tx PTP packets.
  - Ethtool callbacks related to PTP.

Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>