We need priv->ptp_caps to hold a structure and not just a pointer,
because we use container_of in the various PTP callbacks.

Therefore, the sja1105_ptp_caps structure declared in the global memory
of the driver serves no further purpose after copying it into
priv->ptp_caps.

So just populate priv->ptp_caps with the needed operations and remove
sja1105_ptp_caps.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>